First of all if your periods are regular you can predict your ovulation time.
is a hormonal contraceptive
ring,which releases hormones and they get absorbed in the body and act as contraceptive. So once you put nuvaring in the hormonal changes have already begun,and if you take it out in the middle of the cycle you can get your periods anytime due to hormonal imbalance. So what you can do now is wait for your natural periods,and the hormone levels to settle in the body. Once the cycles are regular you can plan for pregnancy
And remember not to play with hormones and your body in such a way.