Oh no!!! Hang in there, 2.5 hours to go!I think they recommend 3 litres (on top of the water used for ur shakes) but no more than 4litres. I have a 1 litre bottle with me and just keep drinking then topping it up throughout the day. Just make sure u spread it out though as it can be dangerous if you drink it all at once. I forgot to get my shake to take to work today so I'm going to have to wait until 6pm for lunch, it's going to kill me lol x