Pregnant or period?

I'm so confused, so my boyfriend and I had sex 3 different times, him finishing inside me all 3. The app says I'm not fertile for another week, but also the app is kind of messed up with my sedcule, because my body has a mind of its own. So I'm not sure if I could be pregnant or what? But here tonight I have some really bad cramps and apparently you can have that as a early sign but it also hasn't been that long since we had sex so I don't know if I'll be able to tell anything right now. It's just the cramps are bad and it's not even time for my period. Any advice ?