I Am My Own Roadblock

I always wondered why dieters could explain to you exactly why their diets failed. Sometimes (most of the time) their explanations just didn't make any sense:
"My diet failed because it included too much ice cream"
(I actually laughed at the person who told me this, but, for the record, I would TOTALLY follow a scientifically proven ice cream diet)
And some explanations really hit home (even though they were hard to hear):
"I couldn't stick to my diet because I made it too hard for myself"
Wow. Read my mind much?
So far on this journey (I hate that term, so cliche, but it IS a journey for me, one that wont end. Ever.) I have lost 25lbs and I have lost 2 sizes (22 down to a 18) and I have finally reached a point where I simply MUST buy new clothes because my current ones fall off of me. I am getting compliments and inquiries from everyone (including my customers) and it's feeling pretty good.
But.
For the last 2 weeks I have totally lost my mind. I haven't been sticking to my diet (which, by the way, isnt a popular diet plan but a bunch of odds and ends taken from other plans with my own tweaking) and I haven't been adjusting my exercise to reflect my overage of calories. I have been hiding from the scale since Monday because I KNOW I have messed up and I am not willing to see how bad the damage is. I know that any weight on that scale will reflect the 4 days of excess sodium, not enough water, and extra poop retained due to a diet rich in pizza and pasta. (TMI, I know)
I havent been to the gym since Monday and I haven't been sticking to my 1hr workouts. I havent started my two a days (which I was supposed to start last week. Consists of 3 2x a day sessions of exercise, 45 mins of cardio and weight training and 30-45 mins of aerobic/yoga at 2 separate times a day).
I have totally dropped the ball. Its sitting in front of me on the floor and I am just staring at it. I have no desire to pick it back up. Because I have done the worst thing I could have possibly done for my weight loss:
I started a challenge.
Let me give you a little background:
Whenever I give myself a weight loss challenge, I always feel pressured and frantic and I lose all knowledge of healthy habits and I crash diet and I binge and I gain and lose and gain and lose and I gain. Notice how I didnt say "lose" after that last "gain". Then i get discouraged and I say FUCK IT and grab the ice cream. Cue violins. 6 months later, Im fatter than ever and more depressed. stop violins. This shit must end. So when I started making gradual changes in October, I told myself that I wouldnt do this to myself again. By November, I was hitting the gym 5 times a week, had my diet under control and was watching the scale move in the direction I wanted to.
I allowed myself to get sucked into a "weight loss challenge" and I figured it would help motivate me. WTF was I thinking? I started the challenge Sunday and I have lost my mind since then. It's like putting strict expectations on my losing has caused my motivation to leave me.
I have totally set myself back. Somewhere in my head, knowing that I didnt have any short term goals in mind allowed me to take it one day at a time, one week at a time. Knowing that I wasnt gaining week over week was good enough and losing was a bonus. Now, knowing that to win this challenge I must lose every week has kind of snapped something in my head.
I am losing it and I must find it.
**Picks ball up**
Thanks for listening.