According to Book of Spells, it would be a ferret... Which I find interesting considering when I played that I was absolutely in love with a guy who reminded me of a ferret lol.
But then, according to Pottermore, it would be a falcon. I disagreed at first because I couldn't see any connection, but then... I've been kind of trapped my whole life and birds represent freedom so... Maybe it would be that?
Buuuuuuuuuutttttt you asked what I think, not what those quizzes thing, so... ... ... Honestly, I don't know! I'm not sure I'd even be able to cast one! I don't have any positive memories that are powerful. All my positive memories fade very quickly, and all my powerful, vivid memories are from trauma. So. No idea!