That's tough man. Hey you should check out some research on the amount of sleep you need. For 95% of people the body needs about 7 hours to get rid of all its toxins (by products of your cells bein active). These toxins, if left to build up will usually have negative effects on your neural patterns (memory and problem solving) as well as your muscles (general fatigue) and metabolism (you might gain weight quicker). All these things are pretty bad but it's totally different for each individual person.