I'm sorry you're going through this and I'm impressed that you are in touch enough with your feelings to articulate it.

There's a lot of great advice in this thread. The best I have is to 1) Join a gym and go consistently. Nothing improves your mood like endorphins. Plus, at 38 you'll be amazed at what kind of shape you can get in. 2) Meditate. Learning to be present and grounded will enable you to decide who you want to be and who you want to be with. One I like is called Quantum Light Breath, particularly the version from Jeru Kabbal. It's a guided meditation so you can do it alone, although it is great in a group as well. Spoiler: It has nothing to do with quantum mechanics or the physics of light. There is a lot of breathing, though.

Good luck.