I put her in the cage last night and she ran around climbing everywhere for and hour then she just went to sleep and has been mostly sleeping since. She wakes up when I open the cage but after I hold her and feed her she just goes right back to sleep. :/
my girls did the same thing!
rats sleep a lot (or so it seems to us humans), and are mostly active at dawn/dusk, only venturing out at other times to drink/eat/toilet.
i wouldn't worry about it, unless she starts showing signs of sneezing or stuff like that. ;]
There are days when I wonder if my girls are still alive, they sleep so much! Usually if I make the food noise they'll forget all about dreaming, too, so unless your rat exhibits other signs of sickness (lethargy, different from sleeping), not eating, drinking, etc, THEN you should worry! But good for you for being observant.