Could be that your operation re-triggered your anxiety disorder and the fever put you over the top. I had something very similar happen to me. After witnessing a trauma at work (which at the time didn't seem traumatic), my body chemistry was thrown out of whack. The next week, another tiny stressor sent me over the edge and I literally tested positive for insulin resistance, hyperglycemia, Cushing's syndrome, and hypothyroidism in the next weeks. After treatment for panic disorder and hypothyroidism, everything is returning back to normal. Keep in mind that I'm a guy who lifts (lifted) weights, did cardio, was/in in good health. I drank too many sodas, but that's another story.
It's very possible you're going through a similar ordeal. Only thing that can heal it is the same ole' same ole'; time, meds, therapy, exercise, healthy diet, relaxation methods.
Here's to a positive outlook. I think you'll be fine. Just gotta wait it out.