when i excert my body to do anything. I immeditly get extremly tired that takes about ten to fifteen min. of whatever I'm doing,if I try to beyond that point I sometimes feel very shakey. Like my sugar is low.Then sometimes the next day I'm so tired I cannot even get myself out of bed. I am so weak I can hardly hold myself up let alone talk what could this be? Or can you give me Ideas of what I could look into on the net. All I know so far is I have sinus tackacardia. I take two heart med that make me feel much better. But Im still having this problems. the shakeness is a new syptom for me. can this heart issue make a person feel this bad? oh. I also take a stemulant when i do I feel a weird feeling in the middle of my chest. witch makes me think maybe a lung issue? I do how ever have my syptoms even without taking the stemulants. Thank you for your time & my spelling its not the bwst.