Nuva ring

How long after you took out your ring did u have a period? I haven't gotten a period since June and I took it out in May. My periods were only 3x a yr before I went on the ring but was told it should regulate my period but it hasn't yet. How do I know when I'm fertile if I haven't got my period yet. I don't wanna waste $ on tests cause their do expensive...need help on what to do. Tia