Am I pregnant ?

My boyfriend came in me about a week ago and 4 days after he did I started bleeding a little bit which is odd because I already had my period that month but it only lasted about 2 days and I didn’t have cramps or anything and now I’ve been having slight back pain and mild cramps and very bad headaches but I don’t get my period till the end of the month could I be pregnant? Im waiting to take a test till the day of my missed period.