What is the best way for a disease free, healthy person to evaluate the side effects of donating blood?

I want to donate blood. I’m not chicken. What I know is that I have a tendency to get faint after the blood being drawn.

Also I have a bit of a panic attack issue whenever I drink caffeine. In all likelyhood these are similar activities for the trigger of whatever anxiety I suffer from. Maybe not, and that’s why I’m asking.

This brings me to a bigger picture issue. What if I have an underlying condition that I don’t know about? Will this donation weaken me at a stage when I need all the help I can get.

My pocketbook cannot spare the expense of my poor man’s philanthropy undermining my own health!

I’d love to hear everything you can share on the subject. Within the next two weeks I hope to decide on donating for a someone in need.

Thanks