I feel bad

Ok so i’m not the parent to ever want to spank my child, I feel like it’s lazy and words can help understand more...

While trying to get my 3 yo son to work on his sounds at home...

he told me no, took the paper, crumbled it up and I smacked his arm. He instantly cried and my heart tore. I never have spanked him or anything. I apologized to him and told him that I loved him, explained to him what he did was wrong.

I never have felt so bad ever. I was spanked as a child for little things and remember how bad it negatively effected me. Am I crazy for feeling bad? Am I a horrible person?