Lea - I had the same thing happen. Yesterday not using FMU as well got a BFP faint but there, yet darker than the previous day, and then today in the morning as I had gotten up only once thru the night, I still got up, and tested just a few hours after and the line still came up yet wasn't as dark as yesterdays. Came up quickly as well. So I will go to the Dr's to get a BT anyway, I think you should too. Lots of sticky vibes.