If you have them, you'll feel implantation cramps in your lower abdomen, in the middle rather than on one side. (It's your uterus that's cramping, even if the implantation is happening in one area.) ...

Implantation—when a fertilized egg attaches to your uterine wall—can sometimes cause brief, period-like cramps that intensify during sex, Dr. Gleaton says. You might also notice mild spotting ...

"Implantation can lead to cramping, spotting, and abdominal pain," Dr. Langdon told Babylist. But some people may not notice any symptoms of implantation at all. Do your best to stay cool, calm ...

Implantation bleeding. "Implantation bleeding is thought to be light bleeding that occurs about 10 days after ovulation," says Washington, D.C.-based ob-gyn Dr. Cordelia Nwankwo.