Implantation Cramps

Jaqueline • Ectopic pregnancy August 2013, still trying.
I'm getting period like cramps in lower abdomen, my period isn't due until 22nd of this month according to Glow. My last period was on the 14th it only last 4days. I BD'd on the 20th, 23rd & 27th. Is it possible I could be experiencing implantation cramps? They just started yesterday & theres no spotting.