Basically my 9 month old dd has not slept through the night for the past 3 months up to a crescendo last night of waking up every 20 mins between 9pm and midnight and then at 2, 3 and 4. I work full time, I breast feed her to sleep each time but am starting to feel at the end of my tether. Any advice of how to get her to sleep through most gratefully received?