Could I be pregnant?

Alyssa
I had sex on the 30th. (A day in my fertile window) and on the 4th it said I was ovulating so I had sex then too. Last night I started to feel slight pain in my pelvic area (don't know how to explain it) and I've had massive headaches and backaches. And I've been sleeping all day the past two days. Could I be implanting? Or could I be pregnant?