Indecisive pregnancy results?

I took two home tests the first was positive and the second was kinda inbetween the negative lin e was clear but the positive sign was faint and i went to the doctors and they took a blood test and it came up indecisive. I was supposed to go back on friday and the lady called me and asked me if i had started yet and i told her yes and she told me there was no need to come take the other test because if i started then it was a sure negative. And i dont think thats true some people do still keep theirs. This was at a airforce medical clinic. Should i listen to the nurse or take another test to be sure?