I had a session of hydrotherapy at my local hospital and it was wonderful at the time, just like being weightless, but the rest of the day I felt dreadful, I had to dose up on painkillers and last night I had hardly any sleep because I had a horrible headache and felt ill. I am wondering if it is an effect of the large amount of chlorine they use in the pool because it is a hospital, and I showered straight after but I was in the pool for about half an hour. My physiotherapist suggested it for my back pain and sciatica but I also have diagnosed fibromyalgia and it was rather like after I went to the osteopath. I have another session booked for next week. Any advice or suggestions please?