Hi, I'm 15 am my boyfriend and I just ha sex last Saturday for the first time. We used a condom with an extra big tip, spermicide, he pulled out, and I took a Plan B about an hour after sex. All we really did was break my hymen. No fun stuff. It's now Sunday a week later and I was supposed to get my period Friday, but I haven't and I've been stressing out all week because of my period. On Tuesday morning I broke out in hives on my arms because I was so stressed but it went away throughout the day. Any ideas as to why I haven't gotten it yet?