I been trying to get pregnant and i had unprotected sex a week ago and 3 days after i got my period could i be pregnant?

Theoretically: Only sure way to know is pregnancy test 4 weeks after the last unprotected intercourse. Less likely pregnant if the period you mentioned is coming at the expected time. Recommend consult with a health professional licensed in your area and consideration of pregnancy test at appropriate time as discussed in consult. All the best.

Usually: Sex followed by a period indicates it was too "close" to your period. (see diagram) The egg is released MIDWAY between periods... You could still be pregnant since some women have documented a menstrual period after conception but it's rare! Hope this helps Dr Z

Period after: Your best option at this juncture is to run a pregnancy test to be sure.