Hi -
Just so you know where I am coming from - I have been through this with both kids - now 8 and 4. My son woke like this - sometimes 3X per night as well as my daughter until 3.5. Then after sleeping well for almost 2 years, at 5, he regressed and began having real sleep difficulties. I read every book, tried every method. Many people (including your pediatrician) may imply that either you are causing it or it will work itself out. Please trust your mothering instinct and know that this advice is complete bunk.
I found out that both my kids had yeast overgrowth and bacterial infections in the gut. It sounds unreal, but it is very common now with children. Yours is so little that you can really make a difference in her outcome of health and prevent so many things I won't go into, if you are willing to go further than the typical.
Something that really helped my daughter without doing any testing was to put her on proibotics and Candicid (a supplement for reducing yeast made by Enzemetica - can get at whole foods). When I first did this, she would sleep consistently when I gave this to her before bed. You can empty the capsule in yogurt or applesauce to give her. There are hundreds of studies you can find that will show you that enzymes and proibotics are not harmful even if huge amounts, but are very beneficial.
Also, you may want to try to change to rice milk or almond milk rather than cows milk. Many times, milk intolerance will inflame the issue. If you are concerned about her getting enough fat (calcium is not an issue, it is equal), add 1 tblsp of cod liver oil (liquid at whole foods) to the milk. My pediatrician told me that I should not in any way worry about change from milk - rice or almond was easily as healthy and often less inflammatory to little immune systems. If there is a yeast problem, this will not make it go away, but it may help her sleep better without a tummy ache. Most little ones like Rice milk better because it is a little sweeter and not as strong of a flavor.
Also, in the middle of the night, try to give her half apple juice and half water instead of milk - even rice milk. Work your way to as much water as she will take rather than putting something on her stomach. She is wanting the comfort, but an hour or two later, you are in a cycle that will be helped by not adding more milk.
There is a great doctor in Marietta who I think is just terrific. He is a preventative med family practiconer. He can help you understand the yeast and possibly the clostridia /bacterial issues and treat it. You have no idea how common this is for children now. Sometimes it does not effect the sleep (but causes anxiety and sensory issues later), but it is still a big deal for the immune system. He does not file insurance, but you can file them and be reimbursed (we have had no issues with getting the reimbursements).
Lee Ralph C MD
###-###-####
110 Lewis Dr Ne
Marietta, GA
There are several books you can probably find at whole foods that are pretty good or you can read on the web about it. There is a book called the Yeast connection which may be helpful.
I can tell you that sleeping through the night is so important! for you and her.
Sincerely, J. - a sleeping mom now.