Please read..and help in any way of information

and my boyfriend had foreplay and things got quite heated and he brushed his dick on my vagina never penetrated in at all. The very exterior of my womanhood and we stopped because we are waiting. But i have missed my period second day. I have never been late before. And am not sure if he came at that moment because i was wet too. All am asking is if there is a possibility that i could get pregnant from that if his cum came out. I really dont want to be pregnant.