PREGNANT??

Hey, so my mums friend just moved in with us and ever since she's been here, all of our periods have been messed up. I got mine early for June.

Fast forward, after my period ended, my Fiance and I had sex. Protected, and he pulled out. That was a few days ago.

Fast forward even more to yesterday, my mums friend gets her period that morning, and I start spotting that same night. I thought it was just my period coming early. Well, I didn't bleed at ALL today. Which is odd.

Is this just my period being irregular due to exchange of hormones? Or is it Implantation bleeding? I need answers, because I cannot be pregnant at this point in time . Thanks!!