No Soda May

I like to challenge myself every once and awhile. But what I find is that my challenges can't be too difficult (let's not forget about No Sugar October.... total bust) or else I struggle and eventually fail.
I can go long periods of time without soda without a second thought. I know the best thing for me to drink is water. A kickboxing instructor was telling us the other day that to find out how many ounces of water you should be drinking, take your body weight multiplied by 0.6 - that's how many ounces. Shoooooot. That's a lot of water!
For the past month and a half, I've been doing a lot worse with my water intake and increasing my soda intake. 90% of the soda is diet but that still has really bad stuff in it. So here is my challenge to myself - All I drink for one month is water (with the exception of my Muscle Milk protein drinks before or after working out). I can do it. Right?
It's only day 7 and it's already been a struggle! All the free soda at work is calling my name. I realize when I eat out, I like to get a drink (Soda, people. Soda). When I was at the Jazz game Saturday night, my date got a big drink and I stuck with my water. But I was dying inside for a DC! I realize how much I would drink soda when I was tired too. No bueno!
I've done a challenge like this before in college and I know I can do it again!