Period-like cramps since 4DPO?

Verushka
Hi everyone, 
This month is the first that I've used an opk, I got a +ve this past Sunday (03/13). Making, possibly, Monday my ovulation day.
Been having mild period cramps since yesterday which is 4DPO, research on the net shows me that it's way too soon for implantation. No other signs though. Some people say that was a good sign for them, others had similar symptoms and AF eventually reared her head. Anyone with similar experiences and had a positive outcome <pun intended😊>. Please share...
Thanks in advance
LadyInWaiting...