Positive digital 4DPO

Let me start with I’m a single woman, using a donor, I haven’t had sex since January, and this is my first time using a donor! Going via the hospital clinic and had scans and testing confirmed definitely not pregnant prior to this and they were tracking my ovulation. We done the first AI on the 4th October and the second on the 5th, I ovulated on the 5th! This was not IVF, this was a syringe to my cervix. Afterwards I was very very crampy so today I took a test just on a whim thinking no chance it’s positive but it was, so I took another and another and another, and a digital. Ended up taking 5 line tests and 2 digitals, all positive!! Different urine samples too! As it’s the weekend I can’t make an appointment until Monday but I’m speechless! I didn’t even think this was physically possible! I definitely was not pregnant before this. And I have never used a donor nor is my ovulation wrong, even if it is, the only semen that has been in me is 04/05 October, I have NOT had sex or any other semen in me or sexual activity since January! This has happened purely from the donor on 04/05 October!!!! I am also NOT on any drugs that would alter a pregnancy test result!