I read somewhere once that it is unrealistic to expect a child under 18-24 mos to sleep for extended periods of time.
Also, another thing that you need to realize is that technically, "sleeping through the night" means that they sleep for 5 hours at a time. So really, she IS sleeping through the night.
I know it's tough--you really just have to take it one night at a time.
My daughter slept for HUGE stretches of time from very early on. My son though, just recently started to sleep for 8-10 hours at a time & he's almost a year! Every baby is different!!!
To make things a lot easier on you, maybe you can consider co-sleeping or having her sleep in a pack n' play or something IN your room or just outside of your room. The closer she is to you, the less effort you have to use!
Good luck & hang in there!!!!