Both of my Peace Lilies has been wilting for weeks
I know that I over fed them with miracle grow which initially caused this. About 5 days later, ran water over them, hoping to wash through. Still wilted, I waited for them to dry out & watered as usual. This is several weeks & still all drooping. All of the leaves are green & so are flower buds. (I have them staked & tied for them to stand, as the foliage droops to the base of the pot & there's a mirror behind each plant so you are seeing their rear in the photos also.)
Looks like you likely need to repot your Peace Lily plants.
Dropping for more then a week or two is a good indicator it's time to move up to a larger container.