21-30 day fast, gaining weight after?

alright so im back again FINALLY!! i totally fell of the fasting wagon for 6 days and felt like CRAP. i totally overate and felt so stuffed and actually hoped i could throw up cuz i could just feel it pressing in my intestines...ewww. so anyway, the fast i did before i broke it was a 5 day fast, and i was doing so good! i got convinced to have dinner with friends, i didn't even want to break it!! that always happens- peer pressure. anyway, i'm going to do at least a 21 day fast now- the first day is always the worst for me. i figure if i can make it to 30 days i can lose about 25 pounds or so, 15 if it's not budging... but when i go to break my fast, i know what to do it with, what foods to eat and how much and everything, but how much weight will i gain back? i think that it'll take probably about 7-10 days to completely start eating again (healthy foods this time!!) so if i'll gain back about 8 pounds, i should probably continue fasting until i'm 8 pounds lighter than my goal weight. ???
cw: 150
goal weight 1: 125
goal weight 2 (if it doesn't work out): 130

so should i fast until i reach 125 or until i reach 117?
okay, comments please!!!! this is a great support forum!