i didnt see olivia benson in baggage! does anyone know where she is ?

I believe that Mariska was still in the hospital for a partially collapsed lung when 'Baggage' was being shot.

Yeah I'm pretty sure she's out of the hospital but is just taking a break to recuperate. She had to go back in after her original hospitalization so the docs (and a few of her co-stars) recommended she take it easy for a while.
P.S. I missed her too! :(

It might have been one of those times when Mariska and Chris had to film at the same time so there would be enough episodes for the season because it has happened a lot of times.