We're having similar problems here - my boys have been impossible to put to bed for the past three nights. We had a great routine of bath, book, bed and they had been sleeping from 7 pm until around midnight (sometimes later) and then straight back to bed with no problems. Now, they either go to bed but are awake again an hour later, or just refuse to go down in the first place (they take turns). Last night we resorted to taking them both out for a walk at 9 pm, and they finally went down after that.
I don't know what is going on. During the day, they barely make it to 2 hours of awake time, and they are still feeding every 3.5 hours instead of 4, and draining their bottles. They're 6 months old on Feb 16th, but closer to 5 months adjusted.
They are also waking up at 6 am, where before they were waking between 7 and 7:30.
Could this be a growth spurt? They are driving me crazy.