It's either the baby or the toddler crying one way or the other 
Somehow my 2.5 yo DD suddenly can't play with her toys for 5 minutes while I feed the 7mo and put him to bed. It's like I've just abandoned her to a pack of wolves, the way she was carrying on.
I used to let her use the iPad for these 5 mins but she became a bit addicted
so had to completely stop that.