I've been noticing this for awhile now. If I'm out anywhere and I don't get some water, I start really dehydrating and feel sicker. I think it's from the low blood volume. It's starting to get to the point where I need to carry water with me everywhere. I was out with my friend yesterday and even though I drank two good sized cups of iced tea and a shake, I was still so thirsty and dehydrated that when we went to another store, I had to buy a bottle of water and drink the whole thing. And just now, I was talking to a neighbor for about forty minutes, and I started to feel like I had to get water, dehydration. I've heard of this over the years with CFIDS patients, but it's really only been hitting me in the last few years.