Do I need more junk food?

I actually got out of bed 'early' this morning to go for a run. 1) We are completely in the Dog Days of August and all the humidity that goes with it 2) Had my locks of love haircut this evening and want to try to preserve the style until tomorrow.
I attempted to run to the start of the Run Around the Square, run the course, and then run home for a five-ish mile run. I try to take advantage of "home-court" when I can. Well I took a wrong turn in the initial neighborhood which added a few blocks and a few minutes of time. But the worst part of the run was that I had ZERO energy. It took me 30 minutes just to do the 5k+ portion! I couldn't even lift my legs on the downhill part.
It was extremely frustrating because it was a simple five miles, no big deal. What made it worse was the last two runs (a track work-out and a very hilly 10.5 mile loop past Magee the morning after Claire was born), I felt the same way. There was nothing left in my tank.
I started to analyze what differences might have occurred that would be depleting my energy sources. And then it hit me - on August 1, I started my first 'diet' ever.
And by 'diet' I mean:
*no bagels/donuts in the morning from work
*no afternoon trip to the vending machine
*no fast food
*all 'rules' are out the door if it's a social event
So as you can see, it's hardly a diet - just a little bit better moderation of fats and sweets (my favorite food group). Regardless, my body depended on those calories for years and now I'm depriving it of its usual energy! Now I have to work in some better foods and fast because these bad runs are killing me!
I don't know if I'll be able to figure it out by Saturday but at least I'll be able to beat today's pace, if by only staying on the correct streets!