O My Gosh Please Help Me

So me and my boyfriend had sex last night which was a day before my period!He had came in me😫but I woke up this morning felling like I'm on my period,I used the bathroom and I whiped and a little bit of blood was in it!So I put a pad just in case i looked and only a little bit was on it as if I was about to end my period!Could I be pregnant?He got me the Plan B pill just in case!Please help me!!