hi, ive been getting dizzy, cold sweats, clammy, heavy head, hearing dims, i see bright fluro colours until i can only see black, i cant stand or sit and have to lean on something and it lasts a few seconds. it can happen at any time during any day. blood tests have been done and everything seems fine including blood sugar levels. other doctors keep shrugging me off. I am now wearing glasses as i cant see far away very well, but usually only when i drive. please advice. Thanks