I Used The Nuvaring As A Birth Control. I Used

I used the nuvaring as a birth control. I used it for 3 weeks like it says than took it out. While it was out, I had unprotected sex. I went on Friday to get another nuvaring to put back in that day, but my pharmacy won't have it ready for a week. Is there a chance I could be pregnant from that week it was out during unprotected sex since I could not put it back in at the day I was supposed to?