I am a 55 year old overweight female. My daily medications are Prilosec, synthroid for hypothyroidism and enalapril for blood pressure. The only surgeries I've had is a tonsillectomy (when I was 5) a parathyroid tumor in 2007 and a bunion surgery in 2010. I also have been told I have a heart murmer that is benign. About 2 months ago I started having episodes of headache followed by teeth chattering, extreme shaking, then vomiting and fever of 101 - 102. The next morning, except for some fatigue and headache, I am fine. The tests I have had are a urine culture, ultrasound of abdomin, several blood tests including testing for thyroid function and blood cultures. The only thing that showed up was a low potassium level (which my Dr said was probably due to the vomiting) and that I had mono sometime in the past. This has happened about 10 times wihin a 6 week period. I can't be sure about every time, but I have been keeping track of my activities, what I eat, etc and the last 5 times are after I've been to my water aerobics class at the local fitness center. It doesn't happen if I work out on the machines or if I just do some stretching in the pool. Only when I've had vigorous activity in the saline solution pool. My Dr feels it it connected to something in the water and I should just quit going. I woud appreciate your input.