I have a green bubble tip anemone and it has not opened in a couple of days. Currently it is in the form of a ring. It has a hole in the middle of it that goes all the way thru. It kind of looks like a Lifesaver right now...
It sounds like it is indeed on its way out. A picture would help a lot, but You may want to take it out of your tank before it kills other inhabitants. Here is a good website for BTA info: karensroseanemones.net - INTRODUCTION