Why do I feel so bad?

I fainted today in front of my grandma who had just woken up from surgery and I feel awful. My grandma was so happy that I came too. Since we can’t stay long, my grandpa and I began saying our good byes. I suddenly felt nauseous and dizzy and told my grandpa I didn’t feel to good fell off the bed, blacked out, then woke up in a wheelchair and nurses surrounded me.

I feel awful because my grandma was already in enough pain. And the fact that she couldn’t do anything probably made her feel horrible.