is it possible?

Me and my boyfriend haven't had sex, because i want to wait til i'm 17, which is about 5 days time. However, we went away with his family and we began having 'dry sex' nude. There were a couple of times the penis went "inside" and being caught up in the moment we didn't think about the situation, but it only lasted about max 5 seconds. On the friday it accidently went in once and i freaked out. Then on the sunday it happened for about 5 seconds about twice. On the 2nd time he had previously came from a hand job which would have been half an hour b4 the accidently insertion. Even though it had dried, could the cum still affect me? Also he said he was always aware when he pre'd...and he promised that he didn't in the space of when he was inside. Then on the monday it happened again but i said no after one penetration and he had urinated before his previous ejactulation, which i believe washes out any remaining semen. Please advice me on the chances of being pregnant...I'm extremely worried!!!
Thanks wb asap!