I watch my weight pretty closely. I heard, or read somewhere, that exercise doesn't necessarily help one lose weight (not that it's not important. But, by itself, it's not a weight reduction strategy.)

My suggestions would be don't keep foods in your home you shouldn't be eating. (And avoid going places that have them.) Limit snacks between meals. Drink plenty of water. If you do snack on something have it be something as healthy as possible and portion it out.

When I do snack, what I tend to snack on is mixed (unsalted) nuts. (I strive to keep my salt intake down to a minimum. Salt tends to cause the body to retain fluids. I can always tell, the next morning, when I've eaten something salty because I'll have suddenly gained a couple of extra pounds. Fortunately they're easy enough to get rid of.) But I don't eat nuts straight from the container I keep them in. I scoop the amount I want to eat out into a cup & when it's empty... it's empty. When I eat nuts I drink water with them. Soda, unless it's diet, & even most fruit juices are full of sugar.

I also don't eat lunch, by the way. I just have a bowl of cereal & fruit for breakfast (possibly some nuts mid-day & then dinner. I do also treat myself to dessert during the evening. If I didn't do that I could weigh even less than I do. But, in my case, the weight I'm currently at is acceptable.) I'm not sure how I eat is the healthiest way to go. I'm sure a nutritionist could design something better. But what I'm doing works for me.

To some extent, I think it becomes a matter of what's really important to you. If you genuinely want to be a ballerina, then you'll do what you must do to lose the weight. But if doing that is simply too difficult, then perhaps majoring in dance, or at least with an eye toward being a ballerina, just isn't the correct path for you? Only you know the answer to that question.

Best wishes...

P.S. Personally, I think the one thing you definitely want to avoid is crash dieting. People who crash diet typically seem to gain it all back & more sooner or later. What's called for here is a healthy dietary regimen you can live with day-in & day-out year around. Perhaps some nutritional counseling, or mental health therapy, might be a good thing to add as well (assuming you're not already doing so) in an effort to resolve any issues that may be behind your emotional eating.