Hello! I Gave Blood Yesterday, And When They Checked My

Hello! I gave blood yesterday, and when they checked my iron levels, the first finger was at 9.3. They suggested trying my other finger, and it was at 14. Today I feel very nauseous and have a headache in the back of my head and in my neck, and my ears feel stuffy. Could me giving blood/my iron levels, and the way I feel today have any links? Thanks for your insight!