Definitely don't, don't DON'T get in the habit of eating because you're depressed. I got in that habit in high school and am now in my 20's and am still trying to break the habit. Talk to your mom, sister, friends, journal, paint your nails, watch tv do whatever but eat for that reason. Great snacks when you are hungry or just need a snack are low calorie, high volume foods like popcorn, fruits, veggies and things with a little protein like yogurt, small serving of nuts, apple with peanut butter (double punch of fiber and protein to keep you full.) Make sure you're drinking enough too. I know when I was a teenager I got most of my hydration from mt. dew and diet coke.
Good luck and good for you for trying to get healthy now!!