Plan B

Guys! On Saturday this guy in talking to, came inside of me. (I thought he was wearing a condom but he wasn't big confusion). We drove down to target to buy the emergency contraceptive, I took it 2 hours after having sex. But the messy part is that I can't swallow pills and I never have been able to. I know it's already a small pill. So, I chewed it and swallowed half. Would that change the effectiveness?? I was supposed to get my period 2 days ago. I'm getting a little nervous. HELP.