Just made my girlfriend cry

I can't do this anymore I've gotten worse I made her fucking cry I don't want to be here anymore now she's being comforted by another man because in pathetic and useless. I just got an urge that I needed to act on mid conversation I started getting ready I just wanted out and that hurt her.

I'm not sure I can live with this I've caused her so much pain in such a selfish way and I'm sure a chemical imbalance can't explain that I'm just the worst.