I do think that too much water is a factor here, but also just the size of the plant compared to the space it lives in. That plant would have been ready to transplant into it's final container at half this size.
There's a common thread I'm seeing here, and I'm not smart enough to give you the exact math, but it's a function of the total amount of space that the plant's roots have to spread out in, and the amount of nutrients available to those roots. When plants get large enough to blossom, they are going to start drawing exponentially more nutrients from the soil than they were before that point.
They will also need access to more water, which creates this paradox that if you overwater, it washes the very minerals that your plant needs right out of the soil.
It's hard to guage what you're growing here, but I don't work with smaller than 14" pots for my transplants. Move her over, go ahead and bring the soil an extra inch or two above the base of the stem. Have all the brown part completely covered. Water the new dirt thoroughly, that will immediately start getting nourishment to the roots.
Now that you're transplanted, take these additional steps as insurance:
1. Spray her down liberally with a full spectrum insecticide/fungicide, and also spray the surface of the rest of the dirt.
2. Cover that dirt with a wood mulch, at least 2" worth. The mulch will create a barrier between the infected roots/soil, and the plant's leaves. It will also keep bugs out, and will help with overheating. Spray the surface of the mulch too.
After doing all of this, test the stalk after 24 hours. If it moves very easily, get a round tomato cage, and tie some string as close as you can to the center of the stalk. For this plant to survive (And also make food for you), it has to be able to put as much energy as it can into effectively using the leaves that remain, as the roots at this stage are probably pretty stressed. Put her somewhere that gets full sun all day if possible. New leaves should start to begin sprouting within a week. Do nothing else but water around the base of the plant at least every other day, and you should see this plant begin to recover. Keep the leaves dry and you will probably not have further problems with wilting.
Diagram in case any of this is confusing: