What Do Stomach Cramps Post Unprotected Sex During Ovulation Indicate?

Ok , so here is the thing i ve been trying to conceive for a year a took a little break because no luck , and I also think I wasn t calculating my ovulation correct, so things didn t work out so well . But I decided to try back again got a clear blue ovulation predictor kit , and I had intercourse around my fertil Windows , and now on my 7th day I spotted once and it went away it followed by mild cramps that whole day , and now I still have mild cramps in my adomen but on and off what could this be and i m not due for my period yet , if everything goes right, this will be my first child !!!