What just happened?

Hey y’all! So I have a luteal phase that is on the short side (10 days). We are not ttc, but my husband slipped up (we use withdrawal and no bashing-we are happy with our decision and totally ok if we have an “accident”) 1-2 days before I ovulated. So I got my period yesterday at 11dpo and today I just didn’t feel right. Like I had no cramps the day before and the day of my period which never happens and then today I have weird pains that are kind of like cramps but not. So, because I’m a crazy person, I took an opk and it was what I would consider positive. Then I took a pregnancy test. Line showed up between 7-10 min. What is going on?? I tested negative at 10dpo. Chemical? Ectopic? Late implantation? Is it an Evap?

UPDATE: Testing again tomorrow morning. Wish me luck!