Can 3 hpts be false positive?

Q : hi, i had a miscarriage 10 weeks ago and havent had a period since. (i confirmed with blood test 3 weeks after that the pregnancy had ended.) i had a blood test done on the 18th feb and it was negative for pregnancy so i went home and was to wait 2 months for period and doc would repeat tests if still no period, but on the 24th i did a home pregnancy test and it was positive, then again the following morning so my doc asked for another blood test to be done. i also did another test today (1st march) and it was positive again, but the nurse mentioned when i had my blood test today that the dr thought i had a false positive, surely 3 tests cant be false can they?