Hi. So sorry to hear about your set back with the arm. That really stinks. You were on a good path and that thwarted your efforts. Remember, you can still be physical in terms of cardio and can manage weight through your eating. :>) I know it is hard. I went through years of weight going on and having great difficulty taking it off. I made some lifestyle changes and slowly have lost weight. But it's hard to keep off.
Yes, all of this can definitely affect your period. And, you may have an issue with your thyroid. If you have unusually long cycles, that is a symptom of a slow thyroid and guess what, so is weight gain. Glad you are seeing your doctor. Let us know how that goes. good luck