*warning* This is a wild ass guess-
Do you know for certain that your pads were bedded in properly? If not bedded in, the pads will not have the optimal interface with the rotor for maximum friction. This lack of friction could be exacerbated by the wet.
How long does it take for you to get your brakes back?
Now you know why they put the "Check your brakes" signs on the highway/tollway.
