since I don't know what "philosophy" really is (and I'm not even sure it really is a thing).

I find it's best to treat philosophy as simply a field of study, albeit one that is odd in that most of the questions asked within the field are loosely tied together at best. (There could be a connection between normative bioethics and ontological questions regarding the nature of nothingness, I suppose, but you wouldn't expect a strong connection from the outset) To do otherwise invites counter-example too easily and I don't think there is much (if anything) to gain in asking what philosophy really is.