Starting Tomorrow

I have tried to juice fast before but I have never "made it through" even a day (on fresh juices). I have done two three day packaged juice fasts. I really want to consume only Granny Smith, celery, carrot, and cucumber fresh juice for AS LONG as I can. I am hoping for 40 days. I am worried about cravings, weakness, and lack of sodium (yes, our bodies NEED it). I will be drinking my morning coffee. Please don't shame me. I don't want to deal with the withdrawal. I am a mother so I am responsible for feeding three people and my daughters are teens so I need to make sure that the STRESS doesn't drive me to self-medicate with chips/ice cream/pizza.
Thanks for any help you can offer. I really appreciate it.