I went thru a period so bleak that rolling in cacti would have seemed a joy. I had entirely lost my empathy. I had begun to think that all men were monsters who went home at the end of the day to practice atrocities upon their families. I was disconnected. Bleak. Literally almost unable to breathe. Every word spoken to me hurt upon my hearing it. I thought I would go for decades and die like that.
However, it passed. It took a long time because I didn't address it as early as I should have. Part of the reason for that is that I was isolated. It was a long time. Seems like a full decade but may have been only 4 or 5 years.
I think it's good you recognized it coming. I believe it is a symptom of a depressive, or possibly obsessive, type state that can be handled. It might take some hard work or it may be a matter of reorganizing your life. Take some walks. Look at trees and birds and things. Exercise. Find your stress triggers and eliminate them or make a plan to handle them head on. You'll get better. You probably just need some time to 'find' yourself again. Sometimes, we all get overwhelmed or lost in a bad attitude and just need to find a way to break the spell.
Look for things that cheer up up and let them do their work.

Take care, Love,
Rebis