She does seem unhappy, although the fact that she's operating on ~3 hours sleep and probably has a massive hangover might play into that. On the other hand, she seems happy when she's getting ready to go out. And if she's not having fun when she's out, then she's sure spending a lot of time not having fun.
I think her unhappiness might just be a result of us seeing the lows and not seeing any of the highs. I'd guess that she's doing her fair share of stimulants while she's out, and that would mesh with the lethargic apathy we see when she comes back and crashes.
Either way, she doesn't seem interested in participating in the apartments to even a minimal degree so unless something changes drastically I think it would be for the best if she left soon (sorry BB). I'm sure she can stay in Barcelona and party without being part of RLC if that's what she wants.