doubting the positve effects of no sugar no flour

Hi! Recently I decided to start a no sugar no flour protocol as advised by Brooke. Besides losing approximately 10 lbs my main goal is to reduce my cravings and urges to binge. In the past I tried to follow a NSNF protocol several times before but I always failed. The biggest problem for me is that I am addicted to diet sodas. I am used to drink sweet drinks (artificially sweetened with zero calories) as I like the sweet taste. I like about those artificially sweetend drinks that they have zero calories but taste very good. I drink them between my meals. I find unsweetend tea, water,… boring.
Yesterday was my first day on the NSNF protcol and in the beginning it was not so difficult. But in the evening after dinner I started to think negative thoughts about the NSNF protocol as I started questioning and doubting if giving up sugar and flour and especially artificial sweeteners (and diet sodas) will have any positive effects for my binge urges. I think my failed attempts in the past were also caused by doubting and questioning the NSNF program.
I also cannot believe that I want to give up those drinks forever because I really love them. I am used to drink diet coke every day and I doubt that I am willing to not continue to do so.
What can I do when those negative thougts about the NSNF protocol and those doubts arise? Why do I think those negative thoughts and question the NSNF protocol?
How can I start to really want to give up sugar, flour and sweeteners?
Yesterday I allowed the urges (with the help of the urge jar) and it was not that hard in the beginning, but what can I do with these negative thougts about the NSNF program?
Thank you very much in advance!