I've had this problem for about a year when I get up into a stand and start walkin my head starts to swim, my body starts to shake and my knees give out I collapse on the floor in a heap and my body continues to shake almost like I'm having a seizure. My arms are flailing and I'm totally aware but I can't stop it. So I just wait in a heap until the symptoms pass. This was not something that happens everyday and I could be walking outside and all of a sudden I'd be laying on the ground. They are getting worse and are lasting much more frequently. Help I need some advice