everytime i stand up i get really dizzy and my vision is completely black and i have to hold on to something for like 30 seconds to preven myself from collapsing. i have already seen a cardiologist i was told to drink 0 caffiene and lots of salt it helped at first but its getting worrse now, worse then before i saw the cardiogist one of the newer symtoms that makes it worse then before is after it happens i get really hot and feel clamy and my heart beats really hard and fast any advice?
thanks, katelyn