Caroline was dealing with their situation by drinking copious amounts of alcohol. That was kind of how she dealt with most situations, and she didn't really see anything wrong with it. However when Klaus was getting onto her about her drinking, maybe she should have thought about slowing down. But what else was there to do here? Not a whole lot.
At least maybe she was starting to make some friends. She was happy to meet the other girl, even if Cat did seem a bit perky. She somewhat reminded Caroline of herself when she'd been human. That was odd, but she could deal with it.
She was already there and working on a drink when Cat arrived.