Question: Could my hormones be out of balance to keep me from losing this additional weight?
I always believe that losing weight needs to be 70% diet and 30% exercise. It's the diet that has the biggest percentage. As you said, you lose weight with mineral diet that you had (550 calories a day) well that's good! I hope you can still follow that same diet as there's nothing impossible in losing weight. if you stick to the plan.
No matter how hard we workout, if the diet is out of whack, it'll be hard to achieve the goal of losing weight. So diet still is the best solution in losing weight and also with good exercise. I hope this helps.