Refusal to give blood to a dying friend-against your religion?

I have a rare blood type that less than 15% of the population shares. Recently, I was delighted to discover that one of my best friends shares the same blood type. I was elated because in the case of an emergency where a blood transfusion was needed, it would be difficult to find a matching donor. When I expressed that we could help each other if the need ever arose, she said that blood was sacred and she couldn't do that. She also mentioned that her religion does not permit the sharing of blood or organs. She said she it wasn't personal, but she wouldn't even do this for her own sister, nor would she ask if she was the one in need. I didn't react at the moment, but I was secretly shocked and hurt over the fact that she'd be willing to let me die instead of giving a bit of blood. We are very close, and this has been tremendous weight over me that I cannot shake. This is so confusing because I know she's entitled to her opinion (and blood), but I don't know what to make of this-I'm VERY upset about it. What do you think about this?