I feel your pain girl. I used to eat a lot as a coping skill to deal with issues with my mood to such an extreme that I was overweight as a teen and was depressed about my appearance as a result.
Now I'm underweight from under eating due to my mood. Sometimes bipolar people can be quite interesting with our mood swings and all, yes?
Never be ashamed for who you are or how you look. Never feel guilty for indulging in things that make YOU happy; a degree of selfishness is healthy for a person. Dye your hair, do your nails, get a tan, get some more clothes, or do whatever you have to do to make yourself happy. Besides, guilt has never helped anybody
I'm confident that you are a very beautiful person. NEVER let anybody make you feel otherwise