Um yeah you're not going to want to Water Fast as your FIRST fast and if you need to concentrate on school.
My suggestion - Start another kind of cleasnse, like just colon cleansing. Or if you're dead set on fasting then go with The Master Cleanse on a long weekend..when you have like 3 days to adapt to the fast and get used to it and know what to expect.
If this is your first fast/cleanse, you'd be in for some detox symptoms that would be a problem like headaches. brain fog. mood swings.etc.
Going into fasting just for the weight loss is never a good idea anyway if you're completley new to this website and cleansing/natural health. etc. Coming up with a bogus plan like fasting fora few days then eating normally WILL get you FATTER. So will getting off the fast and rewarding yourself with pizza or icecream.. you'll get fatter.(I don't know if you're like that, but many people come here and only last a few days and then go on pizza binges because during fasts you get major cravings)