I really need to know this. Why am i treated differently by people?

I think, it's maybe because they arent used to the new you, and since u had been the quiet and closed type before they are discouraged or scared of approaching you. Also there is probably a rumor about you that is spread and they are just scared or something. I would advise you to maybe be more expressive and maybe also ask one of the guys who are most open to you and ask them directly why they/you guys are keeping their distance and ask them if he/they thinks theirs sth. wrong with you or sth. Also maybe some of those guys like you? guys try to be nice to the girls they like, and dont cry. There's also online friends u can talk to, they're always more understanding when ur depressed.