I started taking birth control so my period would stop so that I could have sex. The next month I had my period buy it was 5 days late . Could I be pregnant

Sure you could. Maybe not. There is no way we can know the answer to that but... since you asked "could I be pregnant"... the answer is definitely, "Yes, you COULD be." Really, I COULD be... I'm not, but I COULD be.

Hope I was able to help.