What Causes Lightheadedness And Weakness While Standing From Sitting Position?

Lightheadness and feeling weak when i stand from a sitting position within steps from two to 15-20. things go totally dark lasting bout 10-20 seconds feeling as if I m going to faint. After about 10 sec I m ok. When i feel this way I ve had tiredness accompany this as well-lack of energy. This is the 3rd day.