Soda is yes a addiction and one you need to kick. You can go cold turkey or try to ween yourself off by having a alternative to drink to keep you from grabbing a soda. Going thru the withdraw is something you cant get out of. You will have to go thru it but its worth it. I have been pop free for over two years now. Its one of the best things I did giving up the pop.
What you need to understand is .
First get off the pop and off ASAP.
You will need to learn about whats in what you eat.
And you will need to move (exersise) to burn the calories that you do eat.
Try keeping a journal of how many calories your eating a day just so you can see what your eating. You might be surprised.
But to keep yourself off the pop try to avoid it likes its a diease. Because the more you put it in the catergory of something thats bad for you and that you shouldnt be around the more you will be able to stay away from it.
You have to give it the treatment of what its worth to your body.
This is the best way I can think of to try and help you understand how bad pop really is for you. And dont even consider the diet pop. There is no differance.
I hate to be so dark about this but. I have been there and I know just what I was going thru when I was drinking the pop and I know how I felt once I kicked it.
As for weight watchers I can not comment there as I have been working many diffrent ideas from many diffrent plans and books on getting more healthy.
Welcome and hope to see that you to became a pop kicker.