He was very angry because of a door screen we were putting up and he kept yelling and saying I was lying to him and wasn't listening.  I kept begging him to stop and saying I was sorry. I went inside to get away because he wouldn't stop yelling and started following me at which point I just explode. 

I remember trying to cause as much pain to myself as possible, banging my head and scratching at my face. My boyfriend just kinda watched. He didn't try to comfort me or check if I was alright. Just silence. We have been dating for 3 years and he is usually a lot more comforting and nice during a breakdown, even during an argument. I don't understand why he kept yelling at me. Idk, I just felt it was off and now I'm thinking he just doesn't care about me anymore. I'm not sure what to think, would appreciate any advice. 

All he said after was that he doesn't like being wrong and that is why he was so angry.