I'm a BabyWise mom to two little boys--4 1/2 yrs and 20 months. This sounds like a growth spurt. Feed her as much a possible w/ her last feeding of the night. If you're breastfeeding, feed her as normal from the breast and then add a bottle of breastmilk or formula. (Formula tends to hold them longer, but I was pure breastmilk until 9 months.) At times my boys would drink an additional 8 to 12 oz. from the bottle!!! Then, if she still wakes up, go ahead and do another feeding (preferably before you go to bed! Try to time it around 11pm to midnight) Do an extra bottle w/ that feeding if you need to. After that, if she wakes up, do the BabyWise thing of consoling w/out picking up after 15 minutes of crying. Do NOT give her a pacifier unless you want to be up all night putting it back in her mouth. I know it is hard to listen to the crying without putting that paci in, but she will learn very quickly to soothe herself back to sleep so long as she has a full tummy. I couldn't console my youngest son without picking him up, so my husband did it for me. It wasn't real popular w/ him since he had to get up early to work and I didn't, but he knew it was for a good cause! (The baby learning to go back to sleep on his own.) It may take 2 to 4 nights to get her to soothe herself back to sleep, but you'll know she is not hungry because you've fed her 2 extra feedings. With those extra feedings, her tummy should be good and full for the entire night.
Good luck!!! I know you're exhausted. Whatever you do, follow your instincts as you would if you were fully rested. I find that when I do what is easiest right this moment, I usually make it harder in the long run. I just tell myself to do what I would do if I were fully rested and patient. Sometimes, but rarely, that means I close all the doors between me and the baby and turn on soothing music to drown out the crying when I am COMPLETELY sure that everything is okay but he just wants to be awake in the middle of the night. He can be awake and crying in his bed because he is completely safe.