I have just been taking them for a week now, but had a very bad experience on Saturday just gone. I had gone out with my wife to have a look around a National Trust house, got to the top floor all of a sudden without warning dropped to my knees and nearly blacked out, the sweat was just pouring out of me and i felt sick i didn't even have the strength to let my wife take my jacket off. I did recover after about 20 minutes but today is Monday and i still feel a bit fragile has anyone else had these feelings.