I.Am, it sounds like you have good insight into what your problems are. When you say you don't understand why you can be fine, then depressed for 24 hours, then fine again. I would GUESS (emphasis on guess) that something triggers you into an avoidance reaction, which is the depression, then when you feel comfortable again you come out of it. I'm just suggesting this because that often happens with me.

If you know you're resistant, it may just be trial and error of finding a T and in your first meetings talking to them about your goals and letting them know, hey I'm going to resist, but I need you to keep pushing me so I stick with it. You may have to try a few Ts before you find one who understands how you need to be handled to keep you working towards your goals. Some Ts just listen and some Ts do a full on treatment plan with goals and objectives, etc. It sounds like you need the latter. I have had Ts who weren't so proactive as to actually make me work, but those that do, that set goals and we work towards those goals (and they're always small goals and we take baby steps), those are the ones that I notice I have improvement around, versus the T who listens to me rant about my week. As much as I'd love to rant about my week, my current T works very hard to keep me focused on the present and how to deal with my situation now, not focus on the past, and move forward so I can have the things I want.

So why not try a few different Ts out, explain to them you need goals and objectives and you need someone to really keep you accountable so you stick to it? And you know that you won't stick to it, so maybe you're ready to exercise your own discipline and keep at it. I think you're strong enough to. You are strong enough already to know what your struggling with. It'd be one thing if you didn't know what you were struggling with, but you do.

Best of luck,
Seesaw