I have had some cycle issues as well..
I was in menopause, I was cycling about every 90 to 120 days.. After my RNY I was back to my monthly cycle which was rather disturbing to me..
I asked my bariatric nurse why this was... She told me that hormones are stored in fat and during weight loss all of the hormones that were stored in the excess fat were being released and my body was responding in like, basically back to my normal cycle...My nurse made sure that all of us gals were aware that we would be at our most fertile for up to 18 months post RNY due to the release of all of the hormones during weight loss.
I am now just shy of 7 months out and I am now going back to the menopause cycle, thankfully...
I still recommend talking to your surgeon his/her nurse, your Gyn-Ob or your GP just to make sure... This way they can make a note in your chart...