I second the comment about iron levels. I tried to donate blood and was turned away so I started taking chelated iron. My nurse practitioner put me onto it since it is apparently more easily absorbed and doesn't cause constipation like normal iron supplements. I noticed a pretty big difference in energy level in about a week. Just in time to get pregnant and get fatigued from that!
Good luck! I too am someone who really need a lot of sleep and just have to accommodate that need. I always go to bed early. Screw night parties or looking lame to other people. I have to deal with the consequences.