Welcome, Tasha! I've, too, have struggled a great deal with getting in my own way when it comes to breaking bad habits. I would try, and get really excited about succeeding, but for whatever reason, I'd never actually succeed, and I'd get really down on myself. Eventually, I stopped trying - I just couldn't take any more failure. I figured, heck, if I stopped trying, I'd stop failing! I have type 1 diabetes, and earlier this year, I realized I needed to start taking care of myself or sooner or later, I was going to fall apart (literally.) It was so difficult at first - I kept thinking, I've done this before, and every single time, I've failed - this one probably won't end any differently. I decided to see a counsellor about it, because I knew I needed to get it right this time. I told her, "I've been down this road before, I know where it goes - straight to failure." And she said (and it was a revelation), "You haven't been down this road before - hands down. You've never been here, in this moment, in this situation exactly as it is now, before." And I realized she was right. My thousand past failures did in no way need to dictate what I did from that moment forward. And you know what? Turns out she was right, because here I am 7 months later, and I'm so much healthier than I was.
Anyway, sorry for the long story... I guess I just wanted to say that you've had trouble in the past, but you've never been here before. Now can be your moment.
Starting weight: 192.0 lbs (6/19/2011)
Lowest weight: 154.6 (6/25/2012)
Current weight: 162.8 lbs (1/28/2013)
Total lost: 29.2 lbs
Goal: 132 lbs