People are telling me I’ve changed

I’ve been though quite a lot in the past few years.everykne used to tell me how kind and caring I was and said that I would do anything for anyone.i use to be shy and quite quiet.The only down side to this was that I let people walk over me and I was to nice to say no to peope.Going through quite a lot made me a lot stronger and made me learn to stick up for myself. But I think it’s gone too far.i can no longer take compliments and I’m always snapping at people and being rude.in my head,I know that I’m doing it but I just can’t help myself.My whole family and friends are saying that they miss the old me and I want to be able to be that person again but I don’t know how ! I just don’t understand why I’ve turned so nasty to people!? It’s almost like being nice to people makes me angry and when people give me compliments ,it makes me angry and I don’t know why.