So my boyfriend and I had unprotected sex and he cum inside me in mid April but I took plan b pill after it.  However, we had unprotected sex again but he withdrew this time right before he cum.  Can I get pregnant even if I took the plan b pill the first time we had unprotected sex in mid April?  Plus, i took a pregnancy test three days before my period and it's negative.  Also, I just had my period on the 3rd of May.  But now I feel like throwing up, sick, and I get dizzy often.