Are you on medication? If so, maybe it's time for a re-tuning?

In a way, I guess you could say I'm "stuck" in my therapy. I have progressed a lot over the 4.5 years I've been in therapy, but I can't seem to get over the thing that cracked me up in the first place. And to be honest, I haven't really tried to. Not very hard, at least. Because I lack the motivation. You can't really latch onto something if you're not motivated to do it.

I think this is why my therapist seems to be talking about acceptance WHILE at the same time giving me hope that I can still change. It's all very confusing sometimes. The only reason I can think of for why she isn't giving up on me is because I'm actually not spinning my wheels. I am continuing to work on those things that are challenging but don't feel so impossible. She can give me homework assignments and know that I will at least try to do them.

I agree that 18 months seems to be too early to thrown in the towel. YET, I can see how your therapist may not feel she's being helpful if progress up to this point is only subjective. If she can't motivate you to move in measurable ways, then I do think something is off. Some therapists are more much "action-oriented" than others, I'm guessing.

Could you set an ultimatum with yourself? Like, say I will do X in the next four weeks and if I can't, then I need to find another therapist. X could be as simple as calling a non-profit and asking what kind of volunteer opportunities they have. Tell your therapist this is what you're going to do so she will hold you accountable. If she is unable to hold you accountable and help you meet this basic goal, then some questioning is order, IMHO.