What does implantation cramping feel like?

The BF and I had sex five days ago without a condom- when he came he pulled out, but he was still hard so he wiped off the tip with a baby wipe and we kept going (I know now how incredibly dumb that was, save me the lecture I was really horny and hadn't seen him in a month and a half due to the virus. I wasn't thinking clearly and neither was he).

Yesterday, the day before that, and today my stomach has been hurting, but also gurgling like I ate something bad? I have bad gas and bloating too.

My fertile window began today, but before that, the week he and I had sex I believe my period was over 2-3 days beforehand.

I just have no idea how i can tell if something is off with my body, especially the lady bits. I've always had trouble knowing if something was wrong down there or not.