Question!

SO, quick question for you guys.. 
My period last month was 5/19-5/24, he then did the deed on  5/26, 5/29 and on 6/2. Today I've been having cramps in the lower part of my stomach, kind of like period cramps but it's not due again until 6/16. What do you guys think? Implantation cramps? I already have a little boy, but I've forgot all about this kind of stuff.