Chance of ovulation? please help!?

After being off the pill for the 7 days I accidently missed my first 2 active pills for this month. After starting it on the third pill I threw up the next morning. I have since missed another pill in that pack. Will it still be effective? What are the chances of ovulation occuring? I have been on the pill for more than a year and missed some in the middle of the pack but never so many at the start as well as vomiting. Thanks for your help (: