I can relate to most of what you have written a lot! I am 30 and been alone since my early 20s. I also feel so ugly sometimes I cannot imagine anyone would pick me over the thousands of beautiful woman walking everywhere on the street. Sometimes I get compliments though and I am surprised to realize that other people don't see me that way. It's a weird feeling because I don't really understand what they are saying except for the words. sometimes I think I look good and the next moment I feel like a monster.
And I can relate that you don't like sex. I am afraid of it mostly like it was a physical harm although I think I have a normal sex drive. But I didn't feel like this before I tried it.
Anyway, although this may be something stupid everybody keeps telling you.. if you are 19 now there is no way everything will ever stay the same! I wished for myself that I was still the person I was with 19 but so many things happen in life at early adulthood. you cannot prevent that kind of change.