my embarrassing crush on my coworker mark

hey everyone, i need advice or validation, or maybe both. so there's this guy at work named mark and he's super nice and always making jokes and im not sure if hes flirting but it feels like it because sometimes we make eye contact and i blush. i think about him all the time when im not working, wondering what were doing when im not around. its kinda driving me crazy but in a good way? is this normal or am i just being silly. i hope he doesnt know how much of a mess i become whenever hes nearby lol