The LFS is correct, but it's not a good thing if your anemone is doing this often. It should only happen every few days or so I think. Mine doesn't seem to deflate this often, but that's probably because I'm usually not at home to see it. It also shouldn't remain this way for too long. If it's like that most of the day, you may have an issue. Otherwise, as long as the anemone's color is good, it's staying in one spot and has a good feeding response, it's probably doing well. If it starts losing tentacles, begins to decrease in size (sign of starving) or doesn't stay attached, then you have something to really worry about. These guys can be challenging, so good luck. If you haven't done a lot of research on their care, start now. Some people get lucky and have success with little knowledge, but there's no such thing as a "easy" anemone. . .well, except aptasia I suppose (the weed of the anemone world).