How do I reply to "Lol" or a Smiley Face in Text?

Ok so I've been texting this girl alot lately but all she puts is "Lol" or :) or "Ok"! Simple 2-3 characters messages... Idk if she's trying to say I'm boring but apperently I'm not the only one she does it too so I'm guessing it's just how she is. How do I reply to a text like that? I usually say "so wat r u doing" & she'll reply with a "blah blah! Wbu?" & I'll say "blah blah blah :)" then it would go right back to the commenly used "Lol". I would bring up "What are somethings u do when ur bored" but it always seems to get back to. I don't have a problem keeping a conversation with other girls but she texts me everyday so obviously I'm keeping her entertained if she keeps texting me first. Help....