Up every night....

We are finding out that it is like clockwork that Mae gets up every night at 2 a.m. she eats and goes back to sleep. We are tired and would love to sleep through the night. I know that everyone would tell us to let her cry it out but we have 2 other kids in her room that it will wake up, so we deal with it day after day. I am getting to the end of nursing and I am not really producing very much anymore so I am hoping that once I go to straight formula it will make a difference. She has been a little more fussy lately now then ever. I wonder could it be from getting more formula and less breastmilk and then I start to feel guilty about quitting.....so for right now we are blaming her teeth. She has none yet and she is 8 months so they could very well be going up and down. Lou didn't sleep through the night until she was 1 so maybe we will have to deal with the same thing here.