Confused!

I have been on bc since I was 19 because I was very irregular and when I got my period it would be very heavy and extremely painful. Every month since I started bc my period has come like clockwork. This month, it is late. It was supposed to start Sunday. Monday I thought it had started, but by the next morning there was nothing. I have taken 3 hot and all were negative. Has anyone ever had this happen? Is it possible I could be pregnant?