I agree with everone else here, take some time to educate yourself before beginning the more knowledge you have the easier it will be.
I have little experience fasting, but in regards to concerns about sleeping habits: My first fast for 14 days I slept very little each night my body seemed to require less and less sleep by the end of my fast I was only sleeping 2 to 3 hours a night. Strange thing is I had tons of energy days 4 to 11 I had so much energy I was bouncing off the walls, days 12 to 14 still had ample energy but body was too fatigued and weak to bounce off walls anymore : )
Not sure if my experience with sleep is common hopefully more people will add comments. Fasting effects everyone a little different.