Can't feel what is happening. To me?

I am a normal 24 yr old girl or so i thought before today. I have always cared about others and been the mature friend in my friend circle, like always putting others before me, understanding their issues, providing inputs, caring about them etc. Nobody did the same for me but I am fine. I don’t need them I have always been on my own since I was a kid and I am really okay with it.But from past few months something changed, I stopped caring. I mean, I don’t want to talk to my friends anymore, I don’t care whether they are happy or not. And it’s not like I don’t want to care, it’s just that I can’t . The thing that worried me the most is that I could not feel anything when I saw my mum crying because I was being a non empathetic evil daughter. I am scared what is happening to me? Suddenly I have stopped giving any thought to anybody, including my family...I am really scared guys? What is happening to me? It's like the only thing I care about is me and it's scaring me to be this selfish.