I'm Using Mono-Linyah And Im Trying To Figure This Out.

I'm using Mono-Linyah and im trying to figure this out. Ok, I've been using this birth control since 1/28/16 due to irregular bleeding. I'm only taking the active pills the inactive I just throw away. I still have my 7 day period. My period is back on track. My last period ended March 24,2016 and I missed the first pill of my new pack. I took one pill the next day. March 28, 2016 I had unprotected sex twice and he finished off inside me. I began cramping 20 minutes after. I've been cramping ever since and it gets worse when I lay on my stomach. What's going on here?