Sorry to hear what you're going through. It may sound cringe but praying to god helped me during my tough times.
Talk to your parents and siblings if you're on good terms. If nothing helps talk to a psychologist.
I may get flack for saying this, but right now you have a much bigger problem to deal with, i.e. PIP. Start preparing for interviews during weekends and try to finish your office work diligently.
As for your relationship, no one here knows how serious you were about it. If both of you hadn't considered making it long term, I would say it's better to keep things the way they are right now. I had a pretty bad breakup few years back, but now when I look back, all I can do is laugh about the fact that, I was head over heals for such a shitty person.
It's my suggestion and I might be completely wrong and being a d*ck here. You have to decide what's utmost important to you write now.
Prioritize your physical and emotional well-being, then your work, and then someone else. Wish you all the best.