Pre cum

Patricia
Can you get pregnant off pre cum? Me and my bf started having sex last month and the first time was unprotected. I was worried but I got my period this month. Then weeks later, we started having sex. 2 times with a condom and 3 times without a condom. Yesterday, I had I guess pre period cramps but they hurt a little more than my usual pre period cramps. The last time my pre period cramps hurt was years ago when I was a virgin. But this time it hurt. The pain was in my hips to upper thigh and my lower belly. I need advice please! 
PS- I also read that you can't really get pregnant off pre cum. Cause the sperm are dead sperms but I just want to make sure abs get some advice.