"What are you doing?" - that's a normal conversation starter. "What are you doing?" - that's what people say when you're for instance... walking on your hands. "OH MY GOD WHAT ARE YOU DOING?" - that's what people say when you've just sent them a pic of you biting off a chicken's head.
lol dude, some people just like to write like that. I do it and it doesn't mean anything to me I just like to put it. I dont think is something u think about for a while haha, just dont worry about it✌️
She's asking you what you're up to. And she forgot to capitalize the W it seems. Two questions instead of one could be just holding the? button down too long, or some just do it to be cute, or could be cause she really reallyy wants to know what you're doing.