Worried about my sona being stolen

Got a dm from someone and we talked for a bit. Yeah, I know, but at first it seemed like they actually wanted to talk and possibly be friends, though once I shared my sona with them (I thought they were just curious) they immediately slammed me with „commission me I’m an artist“ completely out of nowhere and kept asking me when I planned on getting more art. I backed out right away, but now I’m nervous. They saw the art I sent them. What happens if they take my sona and try to pass him off as their own? Am I overreacting? I feel like an idiot.