two days-fasting, good or bad?

hy everybody!

nice to 'see' you again, after summer vacation. during the past days i succeded in my fasting, it lasted one week and lost weight :). afterwords, however, i (and that's my only fault:(...)re-gained most of the lost weight, since i then went to visit my parents on vacation and ate pretty much.

well this week end i am planning a fast which, nevertheless, must stop on monday.
my question is, therefore:

makes it any sense to fast for about three days, or better to wait for next week to come, when i'll get the right conditions to start a more long lasting fast?
or do you think i can do both (3days and longer fast)?
PLEASE PLEASE kindly reply to me ^_^!