That is excellent advice. Also do not suddenly get up from a sitting or prone position. Blood pressure tends to fluctuate during fast and getting up too quickly can cause dizziness or even fainting. Try doing some deep breathing to oxygenate your body and sip some water. The weakness should pass. Last time I water fasted, my favorite spot was on the floor, but I only Water Fast when not working, I guess it wouldn't look too professional in the office.