Yes especially if your not using some type of birth controll. Are you and your partner trying to conceive?
If you don't want to get pregnant then at least use condoms. But if you're trying to get pregnant then keep having unprotected sex.
If this was two days after your period began, it's not the best time to get pregnant. If it was two days after your period ended, your chances of being pregnant are stronger. But overall, any given month a couple having unprotected sex only has a 20% - 25% chance of getting pregnant if the timing is right and neither partner has fertility issues.
If you were ovulating and not using protection or using birth control there is always a chance you could get pregnant. If you are avoiding pregnancy I would recommend being more careful and steering away from letting him *** in u...even if protection is being used. You should probably get tested immediately.