Sorry to hear about the job that a kick in the gut on top of Everything else. I know things suck for you right now but you’ll get through it.
There are a couple of books that have Soothed me when I was really down. “Going to Pieces Without falling apart” by Mark Epstein and “Consolations of Philosophy” by Alain de Botton, if you’re a reader check them out.
I just wanted to comment on a few of the things that You have said.
“after we have sex the whole world changes from black and white and stark to color and I feel happy, confident, fulfilled, hopeful, loving, optimistic.”
This sounds like you are using sex to feel these positive emotions and not as an expression of these positive things that already are within you and want to share.
This ties in to the next thing.
“even if I climbed this mountain, would the reward fill the void in my life?”
What do you think? Do you think having sex with your Soon to be ex is all that stands in your way of happiness?
Anyways take care of yourself, people do care and I Know that it sucks right now just don’t ignore the lessons that life is showing you right now.