SOS I NEED AN EXPLANATION

Okay so a month ago I had sex three days before my period and I had a normal 7 day period after. I also stopped taking my birth control when my period stopped. It's a month later now and I am 4 days late on my period. Could I have gotten pregnant and still had a period a month ago?? Is it too early to take a test? PLEASE HELP I'M STRESSING!!!!