(((hugs)))) I'm sorry you struggle so with this. As you noted, it can and does change. Part of your desperation is that you do feel you "can't" stop yourself. You can, with help, but it isn't easy, for sure. If your therapist isn't comfortable treating OCD, you could find one who is. But talk with your T about this again, and again, first. Perhaps she is working on the solution from the actual problem side, rather than the symptom side?

(Such as a T who helps ppl lose weight might not address the weight problem at all, but the underlying feelings of worthlessness, which contribute to the weight gain?)

If your T truly understands the situation you are in, and how your mom is bailing you out, rather than you having to do it, you should see her suggestions openly, imo.

What are you doing to stop yourself? I know it's terribly difficult, but that doesn't mean you can't try. You do need to, and with each success you can feel better about yourself.

If you haven't already, you need to close your bank account and go with cash only. Close the debit card and stop any activity on any charge accounts (you don't need to close them yet, I hope.) You can have your check go to a savings account, and take out cash for what you need, and when it's gone, it's gone. You and your mom both need to go to a therapy session, imo, so that she doesn't continue to enable your out of control spending. Work hard on your issues that bug you, and that might relieve some of the need to spend and get that high from doing so. Discuss meds with your T or your MD, adjustment might be needed.

Just some of my thoughts. TC!