I feel confused...and a little dirty?

i think you're probably over thinking it, compared to what a lot of people do online what you did probably wasn't that bad lol you could just tell him about your feelings and clear things up that way so that nothing gets taken too far :) If you've been talking to him for a couple of months and you like him then it isn't really a surprise that you opened up to him, it can also be much easier to open up to someone you haven't actually met face-to-face so I think you're fine :)