I'm sorry to hear you are going through such a hard time, I've been there myself many, many years ago and know just how rough it can be.
Fasting2goal don't beat yourself up about the 3 or 4 day fasts. I've read many times that stress is bad while your fasting. Also fasting 3 or 4 days is an accomplishment to be proud of. When you get your mind in a good place I'm sure you'll be able to do an extended fast.