Sips of water definitely. I used to feel really sick towards the end of a marathon, until I discovered I was drinking too much! A lot of bigger marathons give out water in bottles, which is great, but I woluld hang onto it and drink most of it. Then I ran a smaller marathon which used cups. I took a couple of mouthfuls, choked, poured the rest over my head and ran on. Result - a massive PB and no nausea. Little and often is the way to go.
And don't worry about peeing - even us girls have to suspend our embarrassment gene for a few hours.................
Simple rule of not trying anything new on race day - so make sure you have tested the kit you plan to wear on the day on a previous long run, keep a note of what you eat/drink before long training runs (the day before as well) so you can eliminate anything that causes you problems, and experiment with gels/sports drinks/jelly babies to se what works best.
As rodeoflip says, take it slowly. You have plenty of time to build up the mileage very gradually so you have less chance of getting injured. Use it and enjoy it. It's too easy to think "I have loads of time" then finding you are trying to cram the training in in the last few weeks. Start now and by Christmas you will be in a great place to start the fine tuning.