Your body is fine, unless the break up ended with a very hard crotch kick. Might want to see the doctor, if that is the case.
Your brain, on the other hand, is all sorts of confused right now. And since that is where orgasms happen, it is not surprising you are having some problems geting cranked up again. Wanting to stay in control, worry, poor body image, self awareness, they can all mess you up badly.
Right now, whether you want to or not, you are grieving, mourning the loss of comforting habits and routines if nothing else. Worried about yourself, and with some guilt over the ending, regardless of how it actually happened.
Grief and pleasure don't mix.
At the moment, your failure to climax is just another worry, which shuts down your ability to orgasm even more every time you try. It can fairly easily become a habit.
So stop trying for a while. Let yourself heal a bit first.
poor you. :( it sort of is a mind over matter thing, unfortunately. both the physical and the emotion stuff you are going through involve letting go. my bet is if you let go in one area, you will be able to in another, and since you (feel you) are unable to let go in the physical area, you can't in the other either. and a lot of that is unconscious process based on the things MM mentions, old habits and routines that have become ingrained. try letting go on the emotional level, even in a small way. there's something to be said for throwing stuff out, deleting old emails, tossing something in the lake, or setting a big pile of crap on fire lol just sayin lol MMs right though, stop the other for a bit and find a different way to let go. for now. this isn't gonna last forever. good luck!
I had the same thing happen to me after my last breakup. Only with me it had to do with the fact that my ex's face kept popping up and when that's the same face that haunts you at night and makes you feel like crying constantly... yeah, it's not all that good orgasm-wise. It went away after a couple of weeks, though. Things like this always do, so don't worry. Like MM said, just give yourself some space to heal.