false positive test??

I'm just wondering.. has any women gotten a false Positive test? And I don't mean any faint lines.. like legit positive. Doctor does blood work and it's negative? Ive had 5 positive tests 2 dollar store tests and the lines were pretty dark. And 3 clear blue digital test that we're all positive. I'm supposedly 4 weeks and 2 days. My doctors appt is tomorrow for blood work. And I'm so nervous and scared that it comes back negative. I know it's silly of me to think like that. I just don't want to get excited just yet until pregnancy is confirmed by blood. I just want to see if there has been any rare cases out of curiosity.