I feel as if I have a mental illness, can someone help diagnose me?

Hi all. I would like some feedback to see if this can be diagnosed. Within the past few years I've felt as if there is something mentally wrong with me. Some general symptoms would include being socially withdrawn, lack of motivation or driving force to pursue meaningful goals, and generally just mentally shut down. I feel disconnected with society in general. I feel like an outsider. I'm 19 years old and I feel completely indifferent from my peers. Would it comes down to parties and social events I'm completely repulsed by the idea of going out. It's not just with parties or concerts, but any public interaction I am extremely uncomfortable with. I used to work at a movie theater and I couldn't stand it. I hated the idea of customer service, I completely despised what is was. I hated being in a situation where I would act completely fake to this other person, and they would do the same back. After quitting there I haven't even applied anywhere else. The only other places hiring are customer service jobs and I really can't do it again. It's so bad that I can barely go to the store. I feel so uncomfortable in public, like everyone is watching and judging me. When it does come down to it though I'm good at faking basic human interactions though. So I come here asking for some input on my current situation. I've done a little research myself and I've found I resemble some traits of Schizophrenia(negative symptoms) or some form of Bipolar Disorder. Any advice is much appreciated, thank you!