Oh poor you. No wonder you're feeling awful when it's so recent. But sit tight - it does get better.
I also feel miserable and so guilty about what my ex must have been feeling. That's the thing about abuse, it puts you in the position when you're always trying to understand your abuser and think about how things seem to them.
I gave myself permission to take an hour when I would stop trying to feel his pain and just feel my own. After all, it wasn't as if I was magically taking away his pain just by trying, so a single hour couldn't do much harm, could it?
When I concentrated on my own feelings, I realized how much relief was mingled in with the grief for the past and anxiety for the future. It really was a sensation of physical lightening.
You've honestly done the hardest bit now. There is mourning for the person you used to love (all the worse if you realize that person never really existed). There is worry about the practical/financial side of things, and the fall-out for your future. But oh, how wonderful it is when you can close your door and keep the bully on the outside.
What you're feeling is normal. It's painful, but it won't always feel like this, I promise.