I cant stop eating unheathy foods because im moving and upset!!!? heellllpppp?

im 13 and 5'6 and 168 pounds. when my parents divorced in 2007 i started to gain weight because i would eat more cuse im an emotional eater( i eat more when upset).i gained 20 pounds in a year. and sinsce the ive gained 20 pounds due to growing and puberty. im moving this summer and ever since i found out i cant stop eatting junk food. i eat skittles and ice cream everyday and because im with my babysitter 98 percent of the day im ordering food alot cause my nanny can only cook pasta . every time i try to stop is stop for about a day and then get bavck to eatting.no matter how much i try i dont seem to have the willpower no matter how much i want to lose weight. it makes me cry sometimes. also my only form of exersise ends tomarow.after that ill go into my school year state with no exersise except P.E. i have tried almost every sport i can think of and nothing ive tried ha been fun for me. ANY IDEAS OF HOW I CAN STOP EATTING UNHEALTHY AND KEEP AT IT? I WANT TO GET TO 135 OR 140 IN THE NEXT YEAR OR SO. but because of the moving im eating more than normal.my usual 1400 calorie diet is down the tiolet,... help!!