Dd is 4 months and is generally a happy little girl but seems to get fussy and cranky after being awake and playing for 45 minutes. I try to follow wake windows and nap times but this is hard when she is fussy and I'm trying to keep her entertained. I'm partly thinking she gets bored although I try alternating with toys etc and part thinking she's tired after this time although this is way under what she should be able to tolerate at her age. Anyone any similar experiences or any tips or advice please?