I am a 26 year old female. My question is, does anyone Know why every time I stand up, I black out? I've had head rushes before but this is different. It's so bad that when I stand up my whole body goes numb, I completely lose my vision, (everything goes black) my lips go completely numb and my tongue does as well and tingly too. I just started a new exercise routine last week and it has been happening since then. I have to sit on the floor when this happens or wherever I am standing. I know I'm breathing properly as I'm not new to working out. I'm 5'8" and weigh 116lbs if that is relevant at all. Can anyone help me? I'd really appreciate it. Thank you!