palpitations

tell me why I have a lowgrade feaver palpitations at times tacicardia mild chest pain leg achs and twitching fatigue body achs this is beengoing on for seven weeks had millions of blood tests hart monitor 4 nights in hostipal ct & MRI of head urine tests and still nothing if I could end it painlessly I would please help the queensland docs are usless they are saying stress because they don't have a clue walking is so hard feel like my legs won't support me I have the shakes and feel weak