4 days before AF could I be pregnant?

Liv

So, my period is due in 4 days and today I noticed a little uncomfort by my uterus. I don't want too say it was cramping.. but almost a pulling. And it only lasted like 10 minutes. Is it just my period coming? I don't get cramps usually until the night before and they are intense. Or could it be implantation?? 10 DPO today.