I'd see someone, a doctor or therapist.
I know how you feel about being bogged down. I'd say, try as many distractions as will work for you. Exercise, art, reading, anything really.
Remember the pendulum. You'll get down, but then you'll go back up again.
The guy - well, that sucks. The thing to remember is you do have a degree of control over it. Maybe it's not going to work out, but you can either wallow, or decide you want to get through it as quickly as possible. I'm not saying decide not to be upset, I'm saying, you can decide to see the positive aspects - at least you tried, that's better than me! lol
I hate thinking things are as bad as they're ever going to get, because life has a way of coming around and proving me wrong. But you'll bounce up again. Everyone always does. It just seems impossible when you're in the midst of it.
Good luck.