What are the chances of 8 false positive pregnancy tests?

False positives are rare. Congratulations! Your user name is very fitting :)

Thank you :)

Even one positive being false is rare, two would be almost for sure.

Is there a reason to doubt ? Medical issues, bleeeding,
Have you missed one or more periods ?
I will assume you are having sex.

After the first or second test, you go to your doctor and do a blood test to confirm if you want normally. But I would say you are pregnant and time to start getting those doctor visits planned.