You are not stupid. I can understand why you would feel that way but you are NOT stupid.
I agree about the cycles of the highs and lows. The good thing about being in a low cycle is the only way out is UP. Sometimes it is a slow climb up but take heart in knowing step by step it can and will happen.
I also agree that looking over the list you made y'day and making solid goals with active steps and time lines on how to change some of those things FOR YOU will be helpful and a way for you to take control of your own life.
The one "benefit" the LBS has that will remain with them for the rest of their lives is the ability to pick themselves up in the very worst of times. Sure, we all have had to do that before but IMO this situation is by far one of the most complex. Now, if I can do it so can you. It will take time. It will take baby steps. It will happen.
I think you might find (or at least I did) that once you start doing things to improve your life you will feel empowered. That is not to say you won't feel sad or angry but a tiny piece of you will feel empowered. And it's pretty good feeling to have.
Just to be clear I am not suggesting you give up on your M or anything of the sort. I am not saying don't be hopeful that something between you and your H can improve. What I am saying is right now the best course of action is to tackle that list you made and get yourself in order. That has to come first.