Ooh ouch, this is a toughie!
First thing I would say is not to skip on dinner. As others have said, try to choose the healthiest options from what you have and hopefully you'll be less likely to snack after your three meals a day. I think if you try going 110% on the sports, 2.5 hours should be enough time to work off a lot of your calorie intake.
Stress and sleep deprivation are probably crucial factors here. Try not to panic about your weight too much, as this can result in a vicious circle. Also, is there any way you can get to bed earlier? It seems overly harsh for you to be forced into such an unforgiving routine.
I wish you the best of luck anyway, and most importantly, don't give up
Sarah x