you can probably assume that your earlier on rather than later if ur getting BFNs on 50mu tests at the docs.
My doctor never does a pee test, he always trusts the ones from the shops! a dating scan is the only real way to know how far u are. hopefully u can go somewhere that bulk bills!
Congrats hun, havent had a chance to say it yet, u being pregnant was my first though when i saw ur status last night!!!