It gets easier. I was a diet coke addict till 3 weeks ago, and never drank anything else. Now I'm downing water like it's going out of fashion! And I'm not craving anything else to drink.
I buy cheap sparkling water, about 15p a 2 ltr bottle from most supermarkets, and add berry flavour, its yum, I manage to drink about 3 to 4 litres a day of this x