I feel like I should know this as a mum my 3 week old has just started evening crying for the last 4 days. She is generally a very contented baby and we sleep well. I don't know if it is just normal evening fussiness or if she is in pain from something. My best bet is tummy pain as she is a very gassy baby, and usually the crying ends up finishing with a big poo or a big vomit or both (she has vomiting issues that we are working on- they are getting less frequent and she is gaining weight well). She is exclusively breast fed. I have considered reflux or an intolerance to something I am eating but surely that would be after every feed not just once at night? The rest of the day she is fine.