Implantation bleeding?

Okay, so call me melodramatic and a hyperchondriac, but I'm seriously concerned. My period ended about a week and a half ago, I only just started having sex a week ago (was a virgin, woot for me). Weve been having sex pretty much every night, and there were only two occasions where he'd put if in without a condom, but due to his sensitivity we'd stop pretty quickly. I've started having light bleeding today, and I've had really uncomfortable lower stomach pain, a headache and I've been so nauseas. Originally I thought I might just be getting the flu but I definitely shouldn't be bleeding right?

I'm freaking the fuck out