Lately I've had 2 episodes (1 coming out of now) where I guess my blood volume becomes too low and I become extremely weak (even more than "normal"), dehydrated, my blood pressure goes down to around 95/60 and my heart starts feeling like it's pounding in my chest. It has been scaring my Mom, afraid she is going to find me unconscious. Once I start loading up on water and salt for a few days it goes away, however, I have a real problem remembering to drink a certain amount every day. My thirst mechanism is screwed up because of medications...so my mouth is always dry, so I can't tell that way. Getting more tired than normal doesn't set off any alarm bells in my head because I just attribute it to the normal CFS. Anyone have any tips to help remember? In some ways I wish they made a monitor like for blood glucose that would tell dehydration/volume levels. Thanks.