Will I every think "Thin?"

I went shopping this weekend. And I kept trying on stuff that was too big for me. I even bought a pair of jeans and a pair of pants that were to big for me that I now need to return. I continue to think I am fat in my head. I found myself- in my head- saying- This can't be tooo big for me. It has to fit. Has anyone else had this problem? Do we ever get to a point where we are not thinking fat? Just curious if I am alone on this.