Why does everyone hate me?

First I would really appreciate it if you could answer my other question “ Why is it so hard to tell if he likes me??” too after you answer this one I need more opinions thanks. So today at lunch my kinda friend ( I call her that because I dont know her that well but shes usually nice to me) Out of no where said “Why are you constantly following us?” And I was shocked I just said “ Why, are you guys talking about me behind my back?” And her friend said no, but you stalk us everywhere, its kinda creepy.” and then she said I see you everywhere, outside, in the library, etc. I just said “I dont have many friends on this team” and she said well talk to people you can at least try. I was trying hard not to cry because shes the same girl that my friend said my ex boyfriend who im madly in love with liked a few months ago. And why she was being so mean to me I dont know. And then my friend Amy whose friends with her and the other girl barely said anything to me in gym class and was talking to other people. That really ticked me off. I’m just so upset because I barely have any friends, and I hardly ever see them, and my ex was so much more than my boyfriend, he was my best friend. we had a much stronger connection than most best friends I see have. I just feel lonely and abandoned, I dont know if he’’ll ever talk to me again, and like in my other questions somedays hell stare at me and it seems like he likes me, and other days hell ignore me and it seems like he likes that . sorry, I know this is long but how do you think I can fix this??? Should I sit with them for lunch tommorow or not??? and can you please answer my other question??? The “Why is it so hard to tell if he likes me”? one?