What intestine is a tube about 10-13 feet long folded inside of the human body

I think the answer is Large Intestine. 

Grade point average. it's literally in the name

Iwould describe it as an overall negative image of themselves.  because they are anorexic, they must sometimes look at themselves as overweight or even obese. however, other people may comment on the being to skinny, which may cause them to see themselves as too skinny at other times.