I suppose when coming off any contraceptive it can take our bodies a while to get back to 'normal'. Have you tried checking you CM or CP? I know it helped me tremendously when my cycles were irregular. I would also suggest charting. I think it helps to pin point O and takes the wonder out of the when you may have O'd and therefore less stress on you.
Even if you temp for a couple of cycles it will help you get to know the rhythm of your cycle even if it is irregular. You'll get to know the signs of pre O.

HTH
Tanya