Pregnant from having anal sex on my period?

Hi okay to start off I know this was really dumb. My boyfriend and I wanted to really have sex for the first time, but then that same day we planned to I got my period a couple hours before. But we had a room and everything already so we went anyways. Instead of having sex we had anal in the heat of the moment, he didn't wear a condom even though we had some, but he didn't bring it because we thought we were going to do anything. Anyways he had cum before we started to do anal but he got a tissue and wiped it all down. Then we started to have anal but it really wasn't anal... He only put his penis between my butt cheeks and it really didn't go in it just was on the surface. But I could feel it trying to go in but it really wasn't all the way. Can I be pregnant? I'm freaking out if I am or not because how could I be? It wasn't really anal, and I was on the first day of my period! Please tell me if I'm just paranoid. I know my lesson now to always always use protection no matter what but this paranoia is killing me. My periods are also sometimes irregular and I sometimes start later or sometimes don't get them at all. But not these past couple of months ( before this incident) they have been regular and on time. I'm supposed to get my next period in exactly two days. But I am still worrying what if I'm pregnant?? I've read so many articles and have made myself honestly worried sick. Please someone tell me if I could be pregnant. I'm planning on getting a test if i don't get my period soon but I just want to know if I'm being crazy and if there's no possibility I could be.