Motivation help

Help! I have always been pretty motivated about exercise (have run marathons, small races, swim, bike,etc). But somehow, this summer, after thyroid surgery, I have lost my mojo. I feel great (did not feel great before the surgery), but I have completely slacked off on the exercise-- even went back to the personal trainer and still cannot seem to motivate myself. I have been in weight watchers for a long time, but even that has lost its appeal to me… just really struggling and looking for ways to motivate myself. I have a fit bit, ww trackers, all the tools I need, but can be derailed at a moment's notice. I am an am exerciser-was always up early to use the elliptical in the basement or go outside--- the gym at work is literally across the street from my office-but somehow I rarely enter lately. What is wrong with me?????