I have a simular problem. I have been diagnosed with really low blood pressure which could be due to not drinking enough. The doctor said to drink a litre of water a day but I cant face it. At the moment I'm trying Volvic touch of fruit (sugar free) and Tesco sparkling flavoured water you can buy 4 really cheap. I know its bottled water but its better than not enough blood reaching my brain. Apparently you can buy tablets that contain salts that dissolve in water and flavour it,also helps with hydration. I havent got them yet but I think they were called SIS