My 8 month old has been sleeping through like a dream from 7 til 7, and has suddenly started to wake at around 12mn for 3-4 hours of grumpiness, not crying but letting us know she is awake, settling herself for 10 mins or so and then waking again. the last couple of nights I have had to resort to feeding her, not done that for months! Any ideas? She isn't cold, doesn't appear to be teething either. Could she be hungry? Is on 3 good meals a day and 3 7oz bottles.