Relationships are weird, but so is everything else in life.
Yeah we can comprehend all these things but really when it all boils down to it, we haven't a clue why things are the way they are.
We all know this, yet we still find a way to cope.
It's called time.
We just seem to go along with it after a while.
As Anoni suggested, you should get some rest.
It's an annoying "solution" to problems because it seems so cliche but you may hear that a lot of people suggest it because it is actually true.
I hated when I went through similar troubles you're facing. It made me feel like nothing was worth doing anymore..
I felt as though I was but a spec on a much larger scale of things that matter in this world.
I've even been driven to unspeakable thoughts..
But one thing that always helped me clear my head so I may figure out how to get through my troubles, was resting.
You may wake tomorrow feeling ok and the littlest thing might set you off again.
But know you won't be as upset as you are today.
Drink some water, to do your body a little bit of physical good.
And get some rest, to help your mind reset to face the problem at hand with clearer thoughts.
Cheers.