The feeling of inadequacy in your mind (related to self) is not all irrational. It has some very concrete evidence of the past. We have a different image of ourselves in our brain than what we truly are or what we possess. The mind is in a conflict now and facing severe agony of emotions in a constant process of rebutting those inadequacies/lackings. You're just one trigger event away from falling into a depression or maybe you already are. Do not console yourself with the ice cream thoughts like 'Overthinking is causing me this." or "These are just irrational thoughts".These feelings of inadequacy are not completely irrational. The more the gap in understanding 'Who/What you are ' vs ' Who/What I believe I am ' will increase the agony and thus the anguish. Write all your inadequacies and bothering on a piece of paper. Write the actions to overcome these adequacies. Write a rough plan to perform these actions. This is a very humbling feeling of accepting all your lackings. This will build your character and will help you make better decisions, will give you a sense of ownership of your life, and will help you achieve more. Don't try to falsely rationalize and compensate for these inadequacies with some sense of entitlement, momentary pleasures, instant gratification, or material possession.
Take the fundamental path and put yourself responsible for that even though it seems harder or appear to be more time-consuming. Decide your actions based on this. 'Upskill yourself'. Begin the process of setting a good example for yourself in the process of combating inadequacies. So when in the future if these feelings of inadequacy strike once again at your doorstep either due to some sad triggering events, you'll already have a solid example of your past to answer your inadequacies. Buying Ice-cream (intended metaphor) for your brain is only a temporary 'feel-good' solution or a very attractive escape strategy. Accepting your lackings, deciding the actions to overcome them, taking responsibility for your actions, and thus taking ownership of your life and persistently performing those actions, everything will teach you the biggest lessons of humility, passion, strength, and develop an everlasting spirit in your life. Ice-creams and Antidepressants won't build your character nor will it crush your feelings of inadequacy, instead it will only hide it in your brain for some time. Embrace your lackings and try to overcome them one by one from your actions.