I had rough sex 3 days ago(1st time). im on birth control and used a condom. i'v had pretty bad cramps since and nausea. could i be pregnant?

Pregnancy unlikely: Using one reliable birth control method correctly all the time, works very well. Using 2 birth control methods works even better than very well. However, life can be surprising sometimes. Thus, if a woman is not getting her birth control pill withdrawal bleeding during the inactive pills, or if she is just worrying about pregnancy too much, she can do a home urine pregnancy test 3 weeks after sex.