4DPO and constant cramping any 2WW buddies???

I'm only 4dpo but have had constant cramping the past 3 days, feels like AF could arrive at any second... I've been PG 5 times before (1 ended in miscarriage and i have 4 children between the ages of 11 and 5) and I don't ever remember having this at all... I did an opk and it was quite dark like a day or 2 before OV when usually in the 2WW there's hardly a line at all... we've been TTC for almost 3 years just hoping it's our turn soon!! anyone else around the same DPO?? xx