I'm sure that people aren't really against you or hating you. But it is a very common feeling for most of us to have every so often, you just seem more sensitive to that feeling than other people.

If people are showing their concern and noticing you then that means they care about you. Let them reach out to you a little, and respond by being polite and maybe deflecting the attention back on to them by asking about their welfare. So if someone says "Hey how are you doing?" you could say "Oh, so-so but I'd rather not talk about it, but tell me how you are?" Most people love to talk about themselves so will be easily diverted by the opportunity you would be giving them.