could I be pregnant?

Hello. So me and my boyfriend have been having unprotected sex. I'm suppose to get my period the 26th of this month but it came early, or so I thought. I checked this morning and I had bled so I put on a pad and around noon I checked again but I hadn't bled much. It was a little. So then I changed pads and I haven't bled since. I don't know if I can be pregnant or if my period is just changing because I just started having sex a month ago for the first time. I'm really worried, if anyone has came across this and it was a false alarm please let me know. Thanks.