Any feed back please!

One of those typical, pregnancy scare posts. 
I had sex last week which was my first week back on my birthcontrol active pills, given that I had my period the week before. 
When I had sex we used a condom, but we took it off later that night and didn't use it 
He pulled out 
Three days later I forgot to take a pill and took it as soon as I woke up. Now I'm cramping really bad and am super tired. Am I just ovulating?