Thank you, Siren!
But that was easy for me. Needles do't scare, nor does the sight of blood, and I didn't feel very different from the blood-loss, either. In fact it was fun as the whole crew was very friendly and cheerful.
Today I received my blood-donor-pass with my blood-type, which I hadn't known before. Everything was fine, so they could use the first donation already to help someone.
Two months after the donation I can donate again, and I will.
Cheers!
Markus