most of us in this world have the same thoughts like ur self, its just looking a diffrent angle ur looking at your self from if you was the have the mirror from ur car in the same place in ur room thre would be no diffrence, its just not what you want to see or others to see when you look at ur self in a natual state driving ur car as there is a subconcious thing in every one to look aa certian way in like a pose we can't control, so don't worry we all have this same problem
I think it really depends on the lighting and angle of the mirror... I would not trust car mirrors though... trust mirrors that are standing and in different lights... so maybe check in your bedroom mirror, in your bathroom mirror and in your hallway mirror or something... :) But car mirrors are pretty bad... lol
Lighting makes a lot of difference when it comes to your complexion. Also, the angle of the mirrors will affect things. Car mirrors are angled and often create a disproportionate reflection (hence the "objects in mirror may be closer than they appear" or whatnot that's on the side view). I'd trust the flat wall mirror.
keep looking at ur face in the car mirrors when ur driving and you might lose your shape at all and then you won't be having that problem anymore. I heard that we all are gonna look beautiful in heaven no matter how fat or skinny we were on earth.