Ever had a negative blood test, and 5 positive hpts, than found out later you were pregnant?

I am currently 11 days late for my period, last week I took 3 home pregnancy tests (two different brands) and got a positive on all three, so Monday I went to the Doctor and got a blood test done - it came back negative. That night, I took another hpt - positive again. Then last night (roughly 36 hours after the negative blood test) I took ANOTHER hpt, and got ANOTHER positive - and this time it showed up even faster and even darker. Has ANYONE ever had this happen? PLEASE, I really need some type of insight. The nurse told me to come back in two weeks, but I really just want some idea as to whether I am pregnant or not. I am still experiencing several pregnancy symptoms, and still testing positive on hpts, but that negative blood test is worrying me so much. I started taking prenatal vitamins today, because I would rather be safe than sorry, but does anyone have any helpful advice? Thanks so much!