I stopped Diet Coke cold turkey some years ago. Was full-on hooked at that point...........2-3 in the morning at work, 2 in the afternoon at work and usually one after work when I got home.  Funniest thing, I took 2 tylenol every morning about 10, and 2 more every afternoon about 2. And at least one more dose of 2 sometime during the evening, because I always had a headache.  

Stopped the Diet Coke, stopped the headaches. I hardly ever, ever have a headache now. Only problem is, when I do have one, I think I'm dying b/c I'm not used to the pain.

I will have a Sierra Mist or Sprite when we stop at Culvers for a meal, but don't generally refill the cup before we leave the restaurant.  I don't miss it. I've tasted Diet Coke since then, and it tastes terrible to me. Funny what the body will tell us if we listen.