Question: I feel weird!! Help?!

Well my bf and I had unprotected sex (the 6th)3 days before ovulation (the 9th) and well it's been 4 days since then.. I feel tired and I have this weird feeling in my uterus.. like it slightly cramps and my boobs feel slightly sore.. could I possibly be pregnant..? We are trying for a baby and I feel like it way to soon to have symptoms??