I also experience partial black outs and dizzyness when I get up from bed too fast :/
I have this very bad.
If i sit down for 5 minutes when standing up a blood rush goes to my head, i start losing all vision and feel lightheaded. Then if sitting down very long, ill collapse and one time it was very hard to get back up.
Its a very serious thing. SOmeone told me I had low blood pressure. and i need more sugar and salt but I dont know. Also twice it was very severe.
I was in school and i couldnt even hold my head up. The back of my neck burned and i was yawning so much i couldnt even stop.
The bell rang and i ran out the door blue spots all over my vision, then i started losing it. then i shook it off raced into the office and the nurse just so happened to be right there at the time. Turns out my face was Plae. like...super pale.
anyway i rested for a while. thats all it takes. its becuase not enough blood is getting to head. It later happened again more everely.
I woke up and i was freaking out. vision was going in and out, could barely move i was so tired, very pale, and breathing so loud i was almost yelling it. i layed down in the bathroom keeping my feet high for about an hour and then i was fine.
OK. biug wall of text but still. Thats my story. Might want to see a doctor. My parents dont think its serious so they dont want me to.