Don't give up! You are a very important person and even though you don't feel like it now, you have something to offer to the world that no one else can.
I think that the suggestions so far are good ones and worth trying, but I wanted to add one more thought. I have been sleep deprived for years and before we found out that I had Celiac and all the docs just said nothing was wrong with me my husband would tell me that being sleep deprived can cause many problems in and of it's self. It can cause health problems and (just to show the seriousness of it) sleep deprivation is a tactic that is used when people are tortured and trying to be broken down. I guess I just share that - not to freak you out - but to tell you that all that is happening to you emotionally has nothing to do with the person you are, but something that is happening to you is causing your mind and emotions to be something that they wouldn't normally be. I wonder if you could also focus on trying to do something that will help you get regular sleep. I know that it would help at least to take the edge off of things.
I really hope you start doing better soon! Keep pursuing your health.