Emergency Contraception Symptoms

Hey guys. So, a little while ago, my boyfriend and I had a night where we were just really in the mood and had unprotected sex. He pulled out, but I was still worried. Just to be safe, I bought the morning after pill and took it, but I had to wait 2 days before I could. The package said up to 3 days after unprotected sex, so I figured it was okay. This was a few days ago. However, today I noticed some blood in my panties, even though my period isn't due for a week, and my breasts were a little tender. Are these normal symptoms for emergency contraception?