C.M.
From birth - about age 5, my daughter was a frequent night waker. Sometimes 5-6x a night just so we could 'tuck her back in'. It was exhausting. For some reason now (she's 5.5) she sleeps through the night MOST of the time. I'd say 1-2x a week she'll wake with a nightmare or wake up and ask us to lay down with her or tuck her back in.
My son (from birth) was a great sleeper. Only in the past few months (he's 3.5) has HE begun waking at night - often for night terrors, the pillow or blanket falls of the bed or he wet through his diaper.
So when one started to sleep through the night, the other would wake! And they share a bedroom!
Seems like no sleep for mom...however I have just learned to go to sleep earlier - usually 9-930 and am used to waking up several times a night. Now I'm up just because I think my body got used to waking up and I drink quite a bit of water at night (workout about 1-2 hours before bed) so I'm usually up to go to the bathroom at least 3x a night!!
It WILL get better!! Kids who are overtired often wake up more. Does she have a consistent bedtime and routine? Get her outside or do an exercise video with her (run around with her even) to get her more tired in the evenings!