PM headaches

I don't know what it is with me anymore but I just seem to always feel so YUCK in the PM's anymore - headachey, lethargic, just all around bad. Its no wonder that I can't make myself go workout. I have like no energy. I need to take some vitamins or something. Also, I'm usually typically a night kind of person but the last few days, I'm going to bed early and sleeping late. I feel like I'm out of it by 9pm. Last night I even almost konked out at the beginning of The Amazing Race - yikes! - I can't miss that! But I managed to awaken myself and forced myself to stay up through it. Then I went to bed immediately at 10pm and was asleep as soon as my head hit the pillow. Weird. Thats happening more and more lately!