So, I'm not saying this in any way to pressure anyone to donate blood. But, fwiw, I have donated many times, and I did pass out once. It was really quite random, neither the first nor the last time that I've donated. Every other time has been fine. So, while I am sure there are some people who will have problems each and every time they donate, it's also possible to have a one-off type of situation. If the first time I had donated had been the time I passed out, I doubt I'd be very keen on trying again! But, just wanted to throw it out there that just because you pass out once, doesn't mean you will pass out every time.
