so i thought my OV day was 20th - tomorrow, as I got it from the Jonas method and my subscription to Fertility Friend had ended

but when i re-registered with fertility friend it said my OV day (well predicted one) was thursday last week and we definitely

that day.
I have been having AF type cramps, would this be implantation cramps do you think? or would it be too early. My cycles have been a bit crazy of late so i'm not sure - hope its Implantation cramps, when do you think i should test??? I'm so excited!