Check out this video by Elliot Hulse (thanks to silent ninja for the link
)
http://www.youtube.com/watch?v=k_FFIFhG6toBut the basic idea is our motivation changes every year, every month, every day and every minute. Don't wait to be motivated to make a change, because that time may never come. You know what needs to be done if you want long-term happiness with yourself, so do it. Even if you don't want to. Get back into the habit and then just stick to it, not just when you feel pumped to lose weight and you don't havs much going on in your life but every day. Do what needs to be done.
For example, this morning I woke up at 5am for some sprints, I wasn't motivated to do them and I was very tired, but I knew if I want to lose weight, get stronger and faster in the future, then this had to be done whether I like it or not.
Next, think about how it feels where you are at the moment. You are giving in to your short-term desires of eating food for comfort, but this isn't making you happy in the long run. Whenever you feel like comfort eating again, remember how disgusting and stuffed you feel after you've done it, try and keep this in mind. Also, remember how good it felt when you were slim again. You felt attractive and on top of the world right? Keep these feelings in mind for the future. Also, from a neutral male point of view, you look really hot when you were slim it would be a shame to give up on that.
Finally, you really need to address your depression. I bet this is one of the biggest reasons for your failure. That constant cycle of getting angry/upset/bored, eating loads, feel disgusting after, then eating loads to combat these feelings. Find another outlet for your emotions. Try some counselling or meditation, go for walks, listen to music, find time for yourself where you can completely relax and do nothing. Now you said you didn't exercise before, but I think exercise is vital (not to lose weight) but for the mental side of dieting. It makes you feel powerful, good about yourself and really lets you take your emotions out of yourself. The important thing is find something you enjoy so it doesn't seem like punishment. This could be jogging, martial arts, walking or even lifting. I don't agree with anti-depression medication because it doesn't address the issue imo and just hides it.
Sorry for the essay, but I've been through exactly what you describe before. It was actually comforting on my part as well to know others have been through this. If you have any more questions feel free to ask or pm me.
Hope this helps and hope it turns out well for you