Pregnancy worry

So I get very very anxious when I have sex that I'm pregnant, I worry about it all the time... I was seeing this boy and we've been having sex with condoms, I know none of them have ever ripped so that's fine. however, the other night things got quite heated and he put it inside without a condom. I'd say he was inside me for a total of 10 seconds (if even) and he didn't ejaculate. however I'm now panicking that there could have been some cum or pre cum on him that could get me pregnant... he ejaculated a while earlier in the night but he went to the toilet afterwards. I asked him did he have any cum on him and he said no and mentioned that he had urinated aswell. I just can't get the worry out of my head that I could somehow be pregnant. someone help!!!!