So about two weeks ago I wanted to re-caulk my shower because I noticed some areas where it wasn't done properly, I followed the directions and thought it looked pretty good, but after the 36 hours when I used the shower all the caulk turned to mush. So I redid it over a week ago now and let it set for over a week and it looks as though it might turn to mush again anyday now. What the heck am I doing wrong??

The area you are doing must still have water, or moisture. You will probably have to let the shower dry out for 3 or 4 days then apply the caulking

Just like said above:

1. Area is wet, moist ( even inside the wall, behind wall covering )
2. Moisture in the bathroom ( even if you don't use shower itself there may be high moisture )
3. Soap / Shampoo / body oils etc. residue on the surfaces
4. Dirt, loose plaster, etc...

Make sure the shower is completely dry. Don't use it for at least 3 days before you caulk. Use hairdryer to help it every day. Use Denaturated Alcohol to clean surface. Apply caulk ( silicone or latex ). Allow to dry for 3 days.

If caulked properly, caulk should last for many years. Try again . It is simple job.

PS.: Can you post few photos of the area you are trying to caulk ? Thanks. Milo