I just repotted 4 azaleas and ~20 hours later they are drooping. Before repotting they were blooming and had very dry leaves, almost like a artificial plant, though the soil was moist. The roots of 4 plants were well watered but a solid mass with very little soil in the original pot. There were no insects visible on the plants or in the soil. I used miracle grow potting soil (seems to be the same as what they were in) with a little miracle grow seed starter soil mixed in.
The white and pink plants looked great and only just started drooping. But two others started drooping hours after replanting. I used liquid miracle gro plant food/fertilizer on those two but still no change. I've read that's not a good idea right after repotting.
They had indirect sunlight today, room temperature, but most leaves and blooms are drooping. Full sun did not help.
How can I keep them from dying?
Is there a specific soil out there I could buy? Other than online, I'm limited to Lowe's, Home Depot, Meijer's, Kmart type of stores.

They are just stressed.. it is common in replanting... give them a couple of days... anytime you move a plant it will stress out for awhile... good luck

Susananne is probably right. However if you are potting them in a pot and not the ground sometimes you will leave open pockets of air directly beneath the roots if you don't shake the soil down to fill in the holes. These open air pockets could also cause such problems. Also you aid it was moist, be sure that you are not overwatering.

Again, I agree with Susananne that it is probably just stress, but just in case these are some alternative suggestions.

Often plants droop from the shock from replanting they usually pull through with care. In the future transplant before budding or flowering because the plant uses more energy to fower and the shock will often kill the flowers but the plant is usually fine the next time it blooms. Another commen problem with transplanting is disturbing. It is best to only loossen the very bottem of the roots and you want to spread them out a little before placing. I usually also make a small cone of dirt in the bottem of the hole that you are planting into that will fit the cone from spreading the bottem of the foot ball