Sleepy tired

I keep waking up at about 3am and can't get back to sleep again. I dream about running when I'm asleep and I think about it when I'm awake. When it comes to feeling the pain on race day I have no fear at all. I honestly don't think I will ever experience as much pain as I did in Bangalore (and even if I do, I don't think it would get that much worse). No... my fear is not being able to stay awake. I really don't want to go there and sleep loads and waste all of that time. I want to stay awake as much as possible. I don't have a good track record for staying awake though. I've stayed awake all night before only to feel completely and utterly rough the following morning. I have twice gone to a conference in Portugal and stayed awake for about 39 hours. I was a mess both times and felt sick and dizzy. So, as I write this I'm thinking that pain won't be an issue... 'sleepy' tiredness will! Fortunately my worst stint will probably be during the night when Kerry is with me, so hopefully our chattering on will take my mind off it.