She's not interested in you. Not that you're a bad guy, just that when girls answer with short things like that over and over again, they're talking to multiple guys and just absorbing as much attention as possible. It's just like girls posting fb pics and saying "I'm so ugly". Immediate response by 50 horny guys looking to move out of the friend zone. Sorry bud.
Good long conversation on lets say WoW's pve.. after that is finished we both just wait for while awkwardly. If I dont say next subject then the conversation dies there. Done, zip, over.
I'm a female and 80% of the time during any PvP or PvE session, the other "girls" (not sure if they're females in real life too, or just acting like they are) won't SHUT UP. We get into an instance "oh your character is so cool", "oh how do you get that pet", "have you seen x video?" It doesn't even pertain to the freaking instance or PvP. This also seems to apply in League of Legends... if your chat is relevant to the game at hand, I don't care. But if you're just trying to chat up strangers about random crap...
Also, when chatting on Facebook, I try to at least reply with a sentence or try to move the conversation along even if I don't give a shit. Then eventually I will make an excuse and leave. I think in this situation she is just bored or busy and can't be bothered to actually tell you, so she's just BSing. Conversations are two way streets.