I had a breakthrough a few years ago during a period of not being able to get my butt in gear.
Motivation is fleeting, so why rely on it to accomplish something as big as this? It's like a really flaky friend that you love to hang out with, but you never know if she's going to bail on you.
I found losing and maintenance a little easier once I accepted that it was more about my committment to just do it even though I didn't want to. And I don't always do it begrudgingly. Most days I'm ok, but I have bad days where I just don't want to do anything that's remotely good for me
Sometimes you just have to break it down into one step at a time, whether you have the motivation or not. I really, really don't want to go into the kitchen right now to prep my breakfast and lunch for the week, but I know I just have to because it will just throw everything off if I don't. I really, really didn't want to go the gym today, but I dug out the sports bra, put on my shoes, tied them, got in the car, drove to the gym, took a nice long warm-up walk and got the job done. For me, it's about the consequences of not doing something.
Sometimes it won't be pretty, but you just have to figure it out- one step at a time.