Brain...freeze?

I have a headache. I ate 1/2 a pint of Ben & Jerry's Stephen Colbert ice cream and my head hurts. It's not unusual anymore. It happens whenever I eat sugar in any great amount. The fact that we've had a bag of candy corn in the office kitchen has not been helpful. A handful of those cost me 3 ibuprofen. Full confession: I preceded the stupid ice cream with stupid 3 tacos from Taco Bell. At 9pm at night. Sigh. Impressive to find myself so filled with shame and regret AGAIN. Every time, every time, every time. I suppose this is the nature of addiction of any kind, but I am intelligent, self-aware, in therapy, for love's sake. Doing it again and again...how does one create the discipline within oneself to avoid it day after day after day?