Hi M.,
This happened with us and it was sooooo exhausting. We tried everything you could possible think of and nothing worked....until we did the tough love. Our daughter new that if she whined or cried long enough we would eventually come in. I think most kids wake up some time in the middle of the night. The issue is whether they can self-soothe themselves back to sleep. We were not even giving our daughter a chance to learn that so she knew all she had to do was make a peep and we would come running. But when it started affecting my work day and moods because of lack of sleep I knew I had to grit my teeth and go for it. I know it can be hard listening to your child cry. But here is everything you know: She is safe. She doesn't need emergency attention. There is nothing wrong with her. She just has been trained to get a reaction from you in this manner, and now she is used to it. The first few nights were tough. I would let her cry for a bit and then go in there just to tell her everything is ok and she needs to go back to sleep. I wouldn't stay until she was back to sleep. Big mistake. Then...the tough part...let her cry herself back to sleep. I know it's hard. But you are teaching her a huge lesson on self comforting and she will sooner than you think be putting herself back to sleep when she wakes in the middle of the night. Now my daughter knows that if she cries I am not coming in there and she goes back to sleep on her own. We do keep the monitor on. And mothers do know the difference between the "there is something wrong cry" in the middle of the night as compared to the "I just want someone" cry. So don't be afraid of something really being wrong with her. You will know. If you get that knot in your stomach, go check on her.
My dauhter has been sleeping through the night for almost a year. And now if she cries in the middle of the night, I know it is for a reason.
I hope someone was able to help you and you can sleep well soon!
Beth