I'm not diagnosed with anything (I've avoided mental health professionals all my life - my parents have never supported me going to one while I've lived with them, and when I lived alone, I figured out how to be happy enough to not feel it necessary to see anyone), but if I had to take a guess, probably depression, generalised anxiety, and either social anxiety or avoidant personality disorder, plus a hefty dose of neuroticism (even though that's not a disorder but a personality trait).
Obviously, self-diagnoses mean nothing, but I'd be extraordinarily surprised if my complete inability to function in social settings or to interact with people was normal. Plus the constant worrying and need for control over everything, and how even the smallest problems feel insurmountable to me at times, and how my emotions constantly swing around and I can go from "I love this person more than I've ever loved anyone!" to "I want to kill them!" to "Oh, they apologized! I love them more than anyone else!" in the span of 2 hours. I'm highly unstable and my emotions have always been extreme and hyperbolic; there is something deeply wrong with this brain of mine.