could I be pregnant?

My husband and I had sex on new years eve, it was protected but the condom slipped off inside me he had jizz on my leg and bottom, and a little inside the condom. I think he did a little inside because some came out when I peed. I don't want to freak him out because he does not want kids right now. how long do I need to wait to take a test? my period was supposed to be this week or next.