I had the same problem a couple of months ago I thought the same thing and I ended up buying a new battery. Then it started again just like you every time I tried to start it in the morning it wouldnt start, anyway to make a long story short. I ended up changing the coil pack, under Ford's recomendation, and at the end it turned out to be the starter... I cant say that is whats going on with your car but give a try.
