If you are thinking these types of things you are having a Fat Attack. Fat Attacks can come on suddenly and without warning. Taken literally, it means that there is something flawed with your body (i.e. fatness) that requires fixing to make the feeling go away. However, this would lead you down a rabbit hole in an endless pursuit of thinness.
A Fat Attack is a legitimate signal from your body. You are legitimately feeling something. By blaming your body you are scapegoating it. Perhaps what you are actually feeling is related to the things you associate with fatness.
Maybe feeling fat represents feeling scared that you won't be successful in life.
Maybe feeling disgusting represents feeling unworthy of love and affection.
Maybe feeling gross represents feeling rejected, hurt and angry.
You get the drill. Next time you are experiencing a Fat Attack, see it for what it is and compassionately ask yourself, "What am I really feeling?"