Hi,

Breastmilk lasts for 3-5 days in the fridge and up to 3 mnths in the freezer part of the fridge. (12mnths in deep freez)
As others have identified, it's normal for it to separate - the "cream" rises to the top and often forms little blobs
I was told this, but also told that after 24 hours the 'goodness' in the milk starts to leave. So, although it lasts that long, its ideal to freeze it as soon as possible.
In fact, RCH (royal children's hospital) wouldn't take my milk if it wasn't frozen within 24 hours.