Tips on fasting while working/at school? (did a 30 day fast early this year)

Hello everyone!

I recently finished a 30 day fast in January. During that time I had no school so the little energy I did have, didn't bother me. However, I did a very very poor job of breaking my fast and I definitely feel horrible for fasting for so long and not getting the benefits like I initially planned on. I want to try again! I have the will power, but I want to know....how do I overcome the "energy" deficiency while I'm fasting? Do I increase water intake? Should I take vitamins? How does one do it? I don't think I want to do another 30 day fast, but I want to at least aim for 14 days.
Also, I take dexedrine for my ADD...it's a stimulant. Should I still take the medication while I'm fasting?