If your baby is very fussy at 3 months old, you might dread the days. You are likely tired and frustrated trying to make your baby happy all day. If this describes you, this is common and there are three primary reasons this occurs. This post will share these 3 reasons and give you 3 tips to get through this frustrating stage based on 10+ years of experience as a sleep consultant. Baby Very Fussy at 3 Months From a Growth Spurt Growth spurts are common throughout the first year. They tend