Holy crap, someone posts about the very real effects of the binge/diet cycle, and the way it negatively affects their mental health, and the overwhelming response is just focus on food more, move more, just get over it, you aren't dieting hard enough! I'm surprised someone hasn't suggested the op should just 'man up'.
There have been several studies that show yo yo dieting to be very unhealthy and with each diet 'failure' most people actually end up getting fatter than they started at (it increases the set point weight).
Also to the poster who suggested WW or slimming world, they are some of the worst. Not feeling restricted on these plans my fat arse!
The chances of losing weight through dieting has something like a 5% success rate (of losing 10lbs or more) and at the 5 year mark that drops to 1%, if that. The only people I know who have successfully kept the weight off have done so by making food restriction and exercise their main focus in life. They become slimming group leaders or personal trainers or spend a good portion of their life at the gym and so on.
OP I would suggest you consider a completely different approach. Firstly your mental health is as important as your physical health, depression is a very real illness and you absolutely should focus on ways to help you deal with it. I personally found a course of CBT (through the NHS) and then daily mindfulness meditation has helped me into recovery from depression and anxiety after 14yrs of suffering.
Then for the eating and body side of things maybe you could consider reading the book Intuitive eating by Evelyn Tribole or Health at every size or Virgie Tovar's books or Jes Baker's books (love her). There are so many people writing and talking about this issue.
I know it's shit not being able to fit on the rides, I really do but maybe these suggestions to diet aren't the answer. I know for me my life was mostly dieting, I was bordering on an eating disorder. I had tried to just not eat for several days at a time, tried to throw up after binges and so many other disordered behaviours. I might still be fat but I am so much happier, food is not the sole focus of my life any more and it becomes less important every single day. I eat better than I ever did and it all comes from the right place. I only discovered all this 2 years ago but in that time I have healed so much and I haven't gained weight.
Fear and shame are not the way to make lasting changes that actually improve your life. I'm just sorry so much of this post is about my personal story but I felt your thread needed a different answer to the usual bullshit eat less, exercise more and just shame yourself thin. Good luck Anchovies12!