I don't want to read and run but from someone who's been in the same situation many times.... I know how you feel. Feels like you're going mad, doesn't it? I'll be honest, like mine, they don't seem to be getting darker so either you're heading for a chemical or you are one of those women -one in 2 million I think they said it was- who have naturally high HCG levels. Have you seen your tests snow white too? If so then it's more likely it's the former.
With that said, there ARE women whom have seen faints for days only for the little fighter to get stronger and latch and give a very strong line all of a sudden one morning so till AF shows up you're not out!
I am crossing my fingers for you!