that crushing pain you're feeling is the grief you're feeling of losing someone you truly love. It's a powerful feeling and it will be like that for a while. But be kind to yourself and don't beat yourself up. My sponsor always tells me that it's okay to feel the emotions, but don't call yourself stupid of dumb for making the choices you made, just have faith in yourself.
Cry your eyes as much as you want, and then pick yourself back up and pray for guidance and do something you like to do. Go hang out with some friends, and just try to enjoy something for you that day. It will be hard, believe it's still hard about a month of being broken up, but you just have to believe that you'll get better and deserve to be happy without him.
My sponsor always said, try imagining a life without your significant other, and what do you see and what do you want out of it.