Blood Drive

We had a blood drive the past two days at school and I had the chance to help out because one of my teachers was managing the drive. I was planning on donating blood yesterday, but my hemoglobin was not the minimum amount to donate. Today, for whatever reason, it was, so I donated blood for the first time. Not even three hours later, I received a phone call from a woman who wanted to schedule me to donate again. I explained to her that I donated today so I could only donate platelets until mid-July, at which time I would be eligible to donate whole blood again. I know the blood bank is always in desperate need of blood and blood products, but jesus, a same-day call?