At this age, this could be teething or separation anxiety or both!
I didn't read the other responses first, so maybe people have already made these suggestions...
Have you considered sharing your bed with your daughter?
I've personally really enjoyed having a family bed... and I have very independent children who are secure in their attachment with me.
If you want more info about co-sleeping, La Leche League or Dr. Sears are great resources.
One of the biggest concerns I hear is "What about my sex life?"
Let's just say that, honestly, this arrangement spices things up because you find new times, places, and ways to make sure your couple-intimacy needs are being taken care of!
I've also heard moms worried about rolling over on their child, and to that I would say: don't consider co-sleeping if you are more than 50 pounds over your ideal weight... and if you take ANY kind of sleep-inducing medication (or drink alcohol) -- these conditions would not let your subconscious be aware of the little one in your bed.
Otherwise, your brain really keeps track of the little one and won't let you roll over on her -- much the same way your sleeping brain keeps track of the edge of the bed and doesn't let you roll out of bed.
Another thing is, remember that this is a very temporary stage! That's something that has helped me through the toughest parts of motherhood -- generally, things are temporary, and let's see if there's anything we can enjoy about the situation while we wait for it to change.
So if she keeps waking up, see if you can enjoy the "extra" albeit midnight time... and then, try to catch a snooze with her mid-day too!