If you haven't yet, go buy The Wonder Weeks app. I've never bought an app before, but this is the best $1.99 I've ever spent. (iPhone user here..not sure of android price.) It's based on the book, but who has time to read a book??
Basically it charts baby's mental leaps. Poor Q has been so fussy for seemingly no reason, among other things, and turns out he's going through his first huge leap! It explains so much. Highly recommend getting it.
Here's a screenshot of Q's anticipated schedule.
Re: PSA: app purchase