Having checked your profile, I must say that your physique looks good. And boxing too, along with the training and gym workouts that goes with it, calories get burnt. And that is what weight gain is about - calorie build up.
But reading your OP, you say that your self esteem is low, and then you start binge eating (I call it comfort eating) - unfortunately the worst course of action you can take.
I have been on a weight loss program for the last 18 months, and I have transformed from someone obese to how I look today, after the loss of five stone. If you scroll down the Losing Weight column of threads and come to my own topic, Weight Loss result in Pictures you will see the before/after sequence of pics.
This was achieved by the following:
1. Watch what you eat. Avoid binge eating, keep your meals average, and snack during the day. Fresh fruit is good. Try to avoid high calorie desserts such as apple pie and custard. Finishing your meal with an apple or orange, or whatever fresh fruit you fancy would be a wise move. Also avoid excess cake, candy, chocolate, ice-cream and anything else that would pile up the pounds. Late night snacking can also be hazardous, as the ensuing night does not allow much calorie burning. If you feel peckish late at night, go for a fruit or fat-free yogurt.
2. I have built up a cardio/fatburn workout on the elliptical in the gym. Starting relatively easy, I gradually built up resistance and duration until at present I can burn up to 1,080 calories in one 50-minute session.
Accompanying this, my running partner and I go out for a run once or twice a week, which I find much more exhilerating than a treadmill. In the summer we run through the woods, in winter, it's through the streets.
This is a long post. I hope my effort in posting will be helpful to you.