Hi, chiming in. My lo is 16 weeks and starting to go through similar. Starting to get really cranky with 'independent' activities such as playmat, swing, sitting in bumbo watching mommy do things (i.e. in the kitchen). I've spent more time playing with her, singing songs, reading etc. Was wondering if it was time to introduce some new toys, and I've also tried altering her current toys (i.e. adding the mobile to the swing where before I just played the music), putting her in the donut pillow in her gym mat so she has a new perspective on the dangling toys. The one solitary activity she still likes is the mobile in her crib.