I had to take a sample of urine too, might be worth taking on just in case?
I drank about 2 pints of water and a cup of tea beforehand and was absolutly bursting by the time I went in for the scan. Even the scanning lady said 'oh my dear your bladder is rather full, you don't need to drink that much next time'!
I was very nervous too but as soon as you get in there and LO pops up on the screen you will feel the most amazing feeling ever. Enjoy it.
Anna x