One of the things I've discovered in my nearly 2 years with SP is that my motivation tends to wax and wane...I imagine that's common for most of us. But I've figured out that, if I just keep doing what I know I need to do even when I don't feel like it, my motivation always comes back around!!
I've struggled for a few months, but kept exercising every day and tracking my food...now I'm finally feeling my spark again!! And the weight is starting to come off again!!