Confused

Natasha

So, I tested with first response twice on 2/13 and once again on 2/15. The first two came back pos with faint lines and the test taken on the 15 was a bfp. I went to the clinic today to confirm pregnancy and the results came back as negative. I was heartbroken and confused. The nurse said it could simply be too early for their test (urine, didn’t do blood test) to detect and to come back on Wednesday. Has this ever happened to anyone else?