Sorry about the tmi

Could this be implantation bleeding? Havent gotten my period but still strangely crampy. AF due in a week and a half. Had unprotected sex but he pulled out, but this week ive been getting headaches, feeling bloated and nauseous, just overall strange. Ive gotten three negatives, but if i conceived when i suspect i did, then i would only be a week and a half into the pregnancy and it would be too early for the test to detect the hormone.