Unhealthy weight ...?

I've struggled with eating habits... I've never truly learned the right way to eat either I completely over do it in a day or just stop eating for half a week I've been trying to get better but I've never seem to get there... years ago I used to go days without eating and now I'm 4'8 weighing 85 lbs... yet when I look at the scale and the mirror idk what to think....