False positive

Bee • 💙💜

*update*

Went to doctors. Faint line, Nurse said possible negative. Got blood work will get results tomorrow. Have now taken 4 tests .. The last is the one from doctors

How rare is this? I'm no where near ready for kids and I had sex 12 days ago. Took an early detection pregnancy test. 2 positives.. been feeling sick since a few days after.. I was on the pill and also took emergency contraception by the way. Just curious if fake positives exist