There was pre ejaculate ... If his penis was erect enough for you to be having sex, it was erect enough to be producing pre ejaculate. And pre ejaculate can contain sperm.
You've had a risk. You should consider Emergency Contraception
You should also consider using condoms for ALL sexual activities, including oral sex. You've not only had a pregnancy risk here, but a significant STD risk.
A Quickie STD/STI Risk Assessment
[This message has been edited by LilBlueSmurf (edited 08-09-2005).]