Donating blood

Hey ladies, I donated blood 2 days ago and I'm really struggling. My biggest concern is my resting heart rate, which is 90 bpm 😰, usually it's in the low 60s! My heart just feels like it's pumping too hard, too fast. I feel calm, but I can't get my body to calm down with me.
Is this a big concern? Do you have any suggestions or advice?
I'm not scared, just ready for my body to be back to normal.