My heart sometimes skips beats and i have feeling very fatigued and out of breath hello, i'm am a 20 year old male, and i have been notcing changes in when i stand up my heasrt rate goes up to around 120, and when sitting it's around 60. my hands and feet

Your : Your case is very complicated with lots of symptoms. I cannot really know what you have. There is a syndrome that might be considered: associated with palpitations, shortness of breath, anxiety, poor circulation, long thin young males with very flexible joints - marfan's syndrome. Again i cannot tell you it you fit this or not. I recommend that you see your physicain again and might want a cardiology referral. Best wishes.