BABY DUST OR NOT

Ladies I'm 8 days away from my period and I've been experiencing mild cramping not bad but isn't it to early for me to start cramping ?? I also had unprotected sex Tuesday the 2nd 33% chance pregnancy and  16 days after my period and again thursday 22% chance Pregnancy the 4th 18 days after my period my cycle is 31 days. Could I be pregnant or not. I had blood drawn yesterday from my obgyn but said it was negative could I be to early ???? Please anyone reading this help me I do want to be pregnant so I'm hoping.