It means the guy is bored or has no life. You could also tell he is a freak because nobody doodles on YOUR paper. Maybe he is your friend and just wants to tick you off
he's gay
i started doing this same thing the second i got heart broken/ felt like killing someone. it probably means like, you dislike something or someone and theres nothing you can really do about it.
It just means you are sketching stars, or drawing them. Doodle means to sketch or draw quickly. It also means you are a good drawer, because drawing stars is pretty hard.