Sounds like your gecko is in desperate need of proper care. It could easily have MBD, sometimes called "rubber bones", which would make it look deflated.
Have you followed the recommendations in a decent care sheet?
You need to dust the feeders, vitamins and minerals, because the feeders we have usually don't supply the proper nutrients the gecko needs.
You have to check the heat, if it's not warm enough, the gecko can't digest its food properly. Turning the heat off at night isn't a good idea either, but in some circumstances, with proper care, it could be okay. I doubt that's the case with your gecko.
Read this care sheet. It's long, but if you read the first post, you'll see what you should do to care for your gecko, and can see where you're going wrong and how to fix it. The rest of the posts go into more detail, but the first post is a good summary.
http://www.geckosunlimited.com/comm...-macularius-demo-video-4-jan-2013-update.html