I'm like you - I need 7-8 hours of sleep a night and I'm not a night person. I drive DH nuts because if I'm up until 11PM, I'm about ready to drop! We have a lot of night owl friends. I'm also up at 4:30 to workout before work as it's the only time I'll get a chance. I'm in bed my 9PM most nights, and asleep on the sofa by 8:30. Party animal - eh? :P
I've also trained for a half and know how physically demanding it is. Really listen to your body. If you need a break (on those days where you're so physically and mentally tired that you think you'll shatter if you move), take one. It won't hurt you to miss a short run or to miss a bike ride once in a while. And tossing in a "recovery week" every three weeks or so where you don't do a run over 6 miles and you generally take it easier is a great way to keep up the enthusiasm and momentum. I have a friend training for a marathon who does her long run every other week and it seems to really help her.
Good luck to you! I hope everything goes well!!!!
Christine
Life is not measured by the number of breaths we take, but by the moments that take our breath away.
Cycle! It's Good for the Wattle; it's good for the can!