NEW TO juicing and SCARED to do it!!!!!!!!!!!!!

Hello,
I am new to fasting but want to start out with juice fasting. The main part i think i am worried about is not having the will power to go that long without food. I have read all over that the first 3 days are the hardest right? I have about 25 pounds to lose but even more so want to do it for good health. I am 31 yrs old and feel like crud...poor diet...3 kids...work full time. I am tired all the time and just dont have energy...i dont know why but i ache i have chronic shoulder pain...and have suffered for 1 yr now...that is another reason i am worried to fast...i have seen massage therapist...chiropractor and so on...doc just put me on pain killers which did nothing for me...

How can i have the will power to fast...i do sit down at a desk job so that wont be to bad...i guess?! I think maybe some encourgement would be greatly appreciated. Going past 3pm without food would be rough for me...any suggestions?
thanks!