mother's day madness

Happy belated mother's day to all of you mommies out there!  In case you are wondering...no, I didn't get my kettlebells (sob).  But, I did get a very nice Bunn coffeemaker, so I am happy. My coffeemaker has been on its last leg for some time now, and I really wanted a Bunn.  The hubby did well.  I decided that I will just buy myself some kettlebells as a celebration for finishing my marathon, which is in 5 days.  Yikes!
This week I am really trying to take care of myself and eat well and get enough rest.  Fortunately, my school semester is out and I have a lot fewer things on my plate this week.  I plan to stretch a lot, run a few little miles, and carb load.
Since it is May and the weather in the Midwest can be a little tricky, I am really struggling with what I should wear.  I hate to be cold when I am running, but it is just as miserable to be hot. Also, I have been carrying my sports beans in my hydration belt, but don't plan to run with it on Saturday.  I'm not sure where I will put those, either!
I am having anxiety attacks over what time I should finish in.  I have to confess that I have aspirations of running a 3:40 marathon.  I have averaged about 8:30/miles for all of my long runs, and so if I look at that, I should be right in that neighborhood.  But, I have never run the last six miles, and I understand those to be the most difficult.  That means I would have to run 8:15 splits in order to account for my slowing down at the end.  I'm not sure if I can do it.
I know I should just go out and run and not worry so much about it. I guess that's just not how I roll.  I think the best thing for my brain is to feel good about finishing anytime under 4 hours.  I think I would be happy with that.