6 years out and steady gaining...

I'm guessing it could be your thyroid nodule. I do know that the thyroid can do some major messing with our bodies. I'm sure once your thyroid gets stable, you'll be back to losing again. Think positive.

I have had multiple surgeries and I dont know what it is, I always gain 10/15lbs through recovery.  And then it takes me a month or so to really get back on track and reevaluate what I am eating, then I will eventually loose it.  

Stick to it, look at what you are eating, and cut down on everything to loose weight again.  

Good luck!