I can not say for sure what this song is about. However, I use to have an eating disorder and all I can say is it describes it perfectly. It actually describes how I was while I was recovering from my eating disorder. I couldn't remember what I was like before I had it and that relates to the "and you really can't remember, but you know you are not, think you are not, know you are not. Who you use to be" Also, your body is freaking out because it gets use to getting little nutrion so now all of a sudden you have all this food and nutrition and you have energy and can't sleep. Or you .."swollow your sleep"