Hi
Welcome to the MedHelp forum!
I agree with Caregiver. Normally, you do not feel anything after blood donation—a human body can easily adjust to that blood loss). Were your hemoglobin etc tested before you donated blood. In all probability you are suffering from hypovolumic shock (a medical jargon—why don’t you just take it as shock) and also there is a huge possibility that your hemoglobin is very low. Drink plenty of fluids and consult a doctor immediately.
Take care!
It's not normal and you probably shouldn't have donated blood. I am offended by the stigma attached by school administrators to students who do not "participate".
It is likely that you have a lowered hematocrit or anemia, common in females. When you donated the number of available erythrocytes to transport oxygen were reduced.
That being said, you will undoubtedly recover fully. Take it easy, drink electrolytes, rest, and the next time you get a check-up have blood work and a hematocrit.