I have had the flu-fever, heavy cough,weakness,body aches,headache, stuffed nose-for three days and I thought I might be getting better but now Everytime I get up and start to move around my heart races to the point that I have to lay back down. It does not go back to normal until I have been laying down at least 10 min. I am a 58 yr old female who exercises regularly and otherwise in good health. Thank you