Each of us are programmed to need a certain allotment of sleep per day. I have learned over the years that when I sleep in later, I'm usually sleeping longer hours which goes over the allotted amount of rest I need. When I get too much sleep, I am sluggish and get less done during the day.
I've found that I'm most productive and creative after I wake up from a sound sleep with just enough rest (sort of like Goldilocks and the Three Bears - it has to be just right).
Anyway, I think you need to learn your sleep/productivity ratio. That's the first step. The next step is to develop a solid routine for bedtime and wake time.
Kim
Self Improvement and Motivation
Fuel-My-Motivation.com