Yes, that was my blood flowing out of my body, into that plastic bag. They took 450 cc, the normal amount for blood donation, about one tenth of the volume of blood in a person. It will be quickly replenished, with no apparent side effects. I have given about 45 times, over 30 years, in 3 different countries, and I have run 4 full marathons in between. It should be OK.
Every 3 months, the Red Cross comes to our campus. Over 5 days, they get 80 to 100+ donors each day. Today, unfortunately, there is a typhoon coming, and they got only about 50 donors. I was actually one of the last to give blood today.
It was surreal, lying there, watching my blood flowing out of my body, while their staff were dismantling the equipment, packing things away, and distributing the unused Chinese herbal soup (originally intended for the blood donors, I believe) among the staff. The staff was kind and courteous. But I cannot help feeling that everyone was eagerly waiting for me to finish.
Still, it is a good feeling giving blood. Join us.