hi mara, I tested 3 days before AF was due (according to "usual" 28 day cycle, but after the mc it aws all over the place!)
I got a very faint positive, wasnt FMU.
if AF isnt on her way, its possible that U have O"d late, and not enough HCG for the test.
Goodluck, hope its a positive for you and nasty old AF stays away! x