I can totally relate. 8 hours is my normal. Less than that means I'm manic. When manic I can function pretty well on 6 hours of broken sleep, but less than that and I am mentally off-agitated, angry, etc.
Right now I am at the other end of the spectrum, wanting to sleep during the day, and taking naps when I can. I am up to 10+ hours on the weekend. I am still working through recent meds adjustments, so I hope after I'm settled I'm back to normal.
Bluemountains