About how many roots are there? Are they all light green?

I think it just needs a couple of days to recover from sitting in water for that long. The flowers beginning to fade doesn't necessarily mean the entire plant is going to die-the plant may just be redirecting more energy to its roots to recover, or perhaps the blooms have just simply reached the end of the lifespan. Once all of the blooms fade, I would cut off the spike at the base with a pair of sterilized scissors (you can rub the blades with rubbing alcohol) to let the plant focus its energy on growing leaves and roots. Doing this will not harm the plant in any way.

Be careful with using sphagnum moss-water only when the moss is dry and the roots are silvery. If the roots are green, that means the orchid has plenty of water and you should not water. When watering, try not to get water in the crown (top of the orchid where new leaves emerge) or in the area where the leaves connect to the central part of the plant.

Good luck!

EDIT-saw Harvey's comment below

I agree-moss is tricky to use with orchids. A growing media based on bark (or other large airy chunks) is much safer and easier to work with.