This evening I experienced what I normally do..The sounds of my heartbeat in my head and neck.I have tried to just blow it off like usualy but I got up earlier today and have been more active than usual..Im so tired and feeling a sense of doom something I cannot shake..Its here then it fades and then its here and then its fades but is quickly overcoming me.I am worried that there really is something wrong with my heart although I have been told there isn't .I can't seem to get my mind off of it tonight as I usually do ...I just have a feeling of dread..like I just have a matter of time before I fade away althoughI dont have any more symptoms than normal..Could I be dying and not know it ..Could there be something more wrong or is it im just more tired than usual..Im really scared and can't seem to relax..How do you know if there is somthing really wrong im just feeling really scared and need someone to tell me what is happening..I normally feel a little worried but tonight I just can't seem to get rid of it..Is this something that happens to dying people or just people that have anxiety ..Please help me ,and tell me what you think.I am not in pain and like I said things seem to be as about usual,why do I feel this worried tonight.? Help please?