I don't think you are strange at all!
I used to be a huge diet-coke drinker, and I still enjoy one from time to time. Not because I crave it, but because I prefer the taste and the fizz.
I also drink a fair amount of sparkling water. Since I have decreased my intake of soda, I find that it is the fizz that I am after, and not the sweetness of the soda.
The only problem with diet soda is that the artificial sweetener may trigger an insulin response. The sweetness that you sense on your tastebuds will trigger an initial release of insulin, because the taste buds are fooled into thinking that some carbs are coming down the pipe. So, in the presence of the insulin circulating in the bloodstream, you begin to feel the sensation of hunger. Therefore, it may toss you OOZ (out of zone).
I think that if you want to enjoy your diet dr pepper, go ahead and have it, but have it along with your meal/snack.