Title says it all but to explain more in detail, I had lumbar spinal surgery two years ago and had a monthly cycle at the same time but I have had no period since? I am having no symptoms of early menopause.

I am 38 years old, obviously female XD I've had blood tests which indicated I had a borderline underactive thyroidgland and so the doctor put me on thyroxine as a precaution. That was nearly 18 months ago and still nothing. ? The surgery was not a success and my bladder and bowel have both deteriorated since and I'm left wondering if my uterus could somehow be affected too but I do not see how? The surgery was very hard going and I spent 30 days in hospital. Could it be that my body has just decided to shut down and my cycle is never going to return? I don't mind however I would like to understand what is going on with my body.