Question: 5 positive pregnancy test but hospital said negative

Hey ladies !!
I've taken 5 test . On Sunday 3/11/18 I took a test (clearbluePlus) and it was neg. Tuesday 3/13/18 I took a clear blue with first morning urine and gotten a very light positive didn't believe it so bought 3 more different brand and they came faint positive. Today Wednesday 3/14/18 ,I went to the hospital and they said it's was negative 🤔 could it because I'm to early ?? How sensitive are the hospitals pregnancy test