It will probably take your body a few months to get back on track. When I stopped the pill, the PCOS symptoms started to show up. It was confusing, because I was mostly fine before I went on the pill, but it's been a slow downward spiral since I stopped (acne, weight gain, messed up periods, hair, etc.) I'm looking to go back on the pill next month because I"m not really sure what else to do at the moment.
I'd say start tracking your periods again after you go off and see how you respond. A great website to use is
www.mymonthlycycle.com If you start to notice changes in your body, keep notes (the website allows you to note symptoms each day of your cycle if you want). Talk to your doctor if things start to get out of hand.