Okay So I Am On The Nuvaring And Use It

Okay so I am on the Nuvaring and use it for 4 weeks at a time and change it on the last day of the forth week and usually have bleeding by the end because my period is trying to start. Well, yesterday like normal I started spotting like my period wanted to come because it was the day before I insert a new ring, I took the old ring out and my boyfriend and I had unprotected sex and he did not pull out and I haven't inserted my new ring yet (silly I know) well now I'm not bleeding at all except some brownish discharged. Could he have got me pregnant and that is the reason my period has not come?