Hi boom6, and welcome to the forum!

I relate to so much of what you wrote, not only taking a long time to figure out what I want to write (this has been the 11 a.m. reply, the 12 p.m. reply, etc.) but the whole cycle of depression and self-sabotage. After thirty-five years of that cycle, I have no easy answers. However, I think you're on the right track here:
I keep writing responses to this, but they end up being about me. However, I'm pretty sure the answer to this question is NOT: laziness, lack of will, etc. Maybe you are swamped - work isn't always just a lame excuse! - and from experience know the amount of effort it took to do a full switch to LC and don't have the bandwith right now. Or maybe eating LC, although it mitigates the depression, does not solve the root cause and somewhere in your psyche, that's become more important than the weight loss. In which case you might try reframing LC as a tool to regain a better psychological state rather than weight loss. Or maybe the ping-ponging cycle you're stuck in is a coping mechanism to avoid something else you're really stressed about. Keep asking the question? Keep observing, noticing. Try to let go of the anger with yourself. As thud said, try to be a friend to yourself. Take yourself on a five minute walk and ask yourself more questions. Listen and observe but don't judge! :-)

Maybe little steps will elude the self-saboteur. Who could object to setting up an innocent little ticker, right? Easing yourself into it might be what works this time around.