Hiya Zebra,
I agree with Hobbit House. I think you make perfect sense. The question is, what to do about it? I wish I had a good answer for that, but if I did I'd be rich.

All I can say is if hobbies are overwhelming right now, concentrate on one hobby, or don't worry about having put them aside for now.
The larger issue is this: "In the past two years I've just struggled to keep focus on anything for more than a few minutes." That's a
long time to be suffering as you are. You have to take care of yourself before you can care for others, and from your own description you're in a place now where you need more help than you're getting. So I urge you to find ways to get more/better help.
As to your relationship w/your b/f, I would say your b/f needs to educate himself about your illness (and
not by talking to you. He needs to be supportive and
understanding to help you through this.
Take the above for what it's worth. I'm not in your shoes so all I can do is make suggestions, as above, and let you know that I and many others here care, and will offer you all the support we can.
all the best,
Randy