I found this today on another forum.... It's the response to people "moaning" that they had lost their motivation (sounds familiar!) and I found it quite relevant for me.
All that motivation will do for you is get you to walk through the door at your meeting, or click on the WW website for the first time. After that, all you need is hard work and perseverance. Motivation is not your friend-- it will leave you at the moment you think you need it most. Sometimes it will come back, and give you a little boost, but then it's gone again in a heartbeat and you find yourself struggling even more than before.
If you want to succeed, it is up to YOU. You have the power, the strength, the stubborness that is required to get through this. None of us can make you follow the program. None of us can provide the push you need to actually get off your butt. YOU are the one who is in charge of your own life. Stop waiting for Motivation!