It's a roller coaster ride. There are good days and bad days and sometimes it takes everything to just get through the moment.
Get DR soon. It will show you there is hope. Have you checked with your library?
Start doing things for you... things you like to do. I know it's hard cuz some of those things probably included DH. Even if you don't have definite plans, I think you should ask DH about those extra nights a week. The weight loss is a good thing. I think we all go through it. Start exercising if you don't already. You'll feel better and look even better with the weight you've already loss.
I understand the pain and the heartache. My DH left in May, too.