pregnant or paranoid?

So in October I stopped taking the depo shot. I had gotten it previous months and it messed my body up so much. Soon after I became sexually active. We are always always always very safe about it. We use a condom and he still pulls out before he finishes, so nothing ever happens inside of me. My period is nine days late right now. I'm almost certain it is because my body is still getting used to things without the shot and I am ridiculously stressed out, but I am still paranoid I could be pregnant. Is there any chance I could be? Or is it probably because of the shot? Please help ease my worries!