Implantation Cramps

Since Sunday night I have been having some very mild cramping on my right lower right side. Then this morning I had two really sharp pains on the same side. These pains lasted like two seconds each and then go away. It feels like a constant pressure, kind of an achy pressure.

Could this be implantation?

Everything that I have researched says women can feel this cramping around 8-10 dpo. This cramping is due to the newly fertilized egg burrows itself into the wall of your uterus however I'm only 4 dpo.

Can implantation really happen this early?