Mum rach - ((hugs)) I'm sorry to be the bearer of bad news, but it sounds like you might have had a chemical pregnancy (a very early miscarriage).
The HPTs will show positive if you have HCG in your urine. Your body doesn't produce HCG - the developing embryo does - so to get a positive test at all, you have to be pregnant. But if BT results are inconclusive, it might mean that although you have HCG in your urine, the HCG levels are not where they should be which could mean that the pregnancy is not developing as it should and you may miscarry. (There is information on the main 1st trimester discussion thread about HCG levels in early pregnancy). (((big hugs))) Chemical pregnancies are heartbreaking - my last cycle ended in one so I know how difficult it can be. You go from being super excited one minute to completely crushed the next. ((hugs)) I really hope I am wrong and you are UTD.

I really hope I am wrong and you get some good news. It could also mean that it is so early that they want to make sure your HCG levels are doubling as they should so just want a second BT to confirm that all is good. I hope so!!