I have a talent for reasoning my way into terrifying and harmful conclusions. The first was modal realism as a fourteen-year-old. Of course I did not understand most of its consequences, but I disliked the fact that existence was infinite. It mildly depressed me for a few days. The next mistake was opening the door to solipsism and Brain-in-a-Vat arguments. This was so traumatic to me that I spent years in a manic depression. I could have been healed in a matter of minutes if I had talked to the right person or read the right arguments during that period, but I didn't.
Lesswrong has been a breeding ground of existential crisis for me. The Doomsday argument (which I thought up independently), ideas based on acausal trade (one example was already well known; one I invented myself), quantum immortality, the simulation argument, and finally my latest and worst epiphany: the potential horrible consequences of losing awareness of your reality under Dust Theory. I don't know that that's an accurate term for the problem, but it's the best I can think of.
This isn't to say that my problems were never solved; I often worked through them myself, always by refuting the horrible consequences of them to my own satisfaction and never through any sort of 'acceptance.' I don't think that my reactions are a consequence of an already depressed mind-state (which I certainly have anyway) because the moment I refute them I feel emotionally as if it never happened. It no longer wears on me. I have OCD, but if it's what's causing me to ruminate than I think I prefer having it as opposed to irrational suppression of a rational problem. Finding solutions would have taken much longer if I hadn't been thinking about them constantly.
I've come to realize that this site, due to perhaps a confluence of problems, was extremely unhelpful in working through any of my issues, even when they were brought about of Lesswrong ideas and premises. My acausal problem  I sent to about five or six people, and none of them had anything conclusive to say but simply referred me to Eliezer. Who didn't respond, even though this sort of thing is apparently important to him. This whole reaction struck me as disproportionate to the severity of the problem, but that was the best response I've had so far.
The next big failure was my resolution to the Doomsday argument.  I'm not very good yet at conveying these kind of ideas, so I'm not sure it was entirely the fault of the Lesswrongers, but still. One of them of them insisted that I needed to explain how 'causality' could be violated; isn't that the whole point of acausal systems? My logic was sound, but he substituted abstractly intuitive concepts in place of them. I would think that there would be something in the Sequences about that.
The other posters were only marginally more helpful. Some of them challenged the self-sampling assumption, but then why even bother if the problem I'm trying to solve requires it to be true? In the end, not one person even seemed to consider the possibility that it might work. Even though it is a natural extrapolation from other ideas which are taken very very seriously by Lesswrong. Instead of discussing my resolution, they discussed the DA itself, or AI, or whatever they found more interesting.
Finally, we come to an absolutely terrifying idea I had a few days ago, which I naively assumed would catch the attention of any rational person. An extrapolation of Dust Theory  implied that you might die upon going to sleep, not immediately, but through degeneration, and that the person who wakes up in the morning is simply a different observer, who has an estimated lifespan of however long he remains awake. Rationally anyone should therefore sign up for cryonics and then kill themselves, forcing their measure to continue into post-Singularity worlds that no longer require him to sleep (not that I would have ever found the courage to do this).  In the moments when I considered it most plausible I gave it no more than a 10% chance of being true (although it would have been higher if I had taken Dust Theory for granted), and it still traumatized me in a way I've never experienced before. Always during my worst moments sleep came as a relief and escape. Now I cannot go to sleep. Only slightly less traumatizing was the idea that during sleep my mind declines enough to merge into other experiences and I awake into a world I would consider alien, with perfectly consistent memories.
My inquiries on different threads were almost completely ignored, so I eventually created my own. After twenty-four hours there were nine posts, and now there are twenty-two. All of them either completely miss the point (always not realizing this) or show complete ignorance about what Dust Theory is. The idea that this requires any level of urgency does not seem to have occurred to anyone. Finally, the second part of my question, which asked about the six-year-old post "getting over Dust Theory" was completely ignored, despite having ninety-five comments on it by people who seem to already understand it themselves.
I resolved both issues, but not to my own satisfaction: while I now consider the death outcome unlikely enough to dismiss, the reality-jumping still somewhat worries me. I now will not be able to go to sleep without fear for the next few months; maybe longer, and my mental and physical health will deteriorate. Professional help or a hotline is out of the question because I will not inflict these ideas on people who are not equipped to deal with them, and also because I regard psychologists as charlatans or, at best, practitioners of a deeply unhealthy field. The only option I have to resolve the issues is talking to someone who can discuss it rationally.
This post  by Eliezer, however unreliable he might be, convinced me that he might actually know what he is talking about (though I still don't know how Max Tegmark's rebuttal to quantum immortality is refuted, because it seems pretty airtight to me). More disappointing is Nick Bostrom's argument that mind-duplicates will experience two subjective experiences; he does not understand the idea of measure, i.e. that we exist in all universes that account for our experiences, but more in some than others. Still, I think there has to be someone out there who is capable of following my reasoning- all the more frustrating, because the more people misapprehend my ideas, the clearer and sharper they seem to me.
Who do I talk to? How do I contact them? I doubt that going around emailing these people will be effective, but something has to change. I can't go insane, as much as that would be a relief, and I can't simply ignore it. I need someone sane to talk to, and this isn't the place to find that.
Sorry if any of this comes off as ranting or incoherent. That's what happens when someone is pushed to all extremes and beyond. I am not planning on killing myself whatsoever and do not expect that to change. I just want help.
 http://lesswrong.com/lw/l0y/i_may_have_just_had_a_dangerous_thought/ (I don't think that the idea is threatening anymore, though.)
(The insert-link button is greyed out, for whatever reason.)