Our
toadstool did that about a month or 2 ago. It was pale, no tentacles out and shrivelled up. It was shedding and did have a baby toadstool come out near it. Then it completely unattached itself from the rock it was attached to. I found it on the bottom of the tank. I took that to mean it was unhappy where had been. (It was somewhat close to a frogspawn which I think was stinging it.) I glued it to a new rock and placed it in a different part of the tank. It took a day or two to come around and then tentacles started reappearring. It looks great now. So does it's baby.
Good luck and keep us posted. You may want to try moving it. Maybe it is not happy with the flow its getting.