I always thought I'd be a blood donor (my family are big blood donors--my stepdad has donated literally gallons over the course of his life), so when I was 17 I was glad to be old enough. We had a blood drive at our high school and I had no problems, just gave it, ate the cookies and went to third period. I got up from my desk at the end of class and felt so weird. I went to fourth period, got in the door, looked at my friend and that's all I remember. I passed out (later found out my friend caught me and carried me down to the nurse!) and had to go home. I was out of it all day. I felt so horrible I've been scared ever since to try it again. I've been anemic on and off since, too, so I've never tried again. I didn't really feel n* though, just light-headed.