19wk old DS has just started to sleep for longer than 50 minutes (thank fuck that's over) and that's LOVELY except that he now won't nurse to sleep (usual tactic for the last 19 weeks) but instead arches his back away from the boob, wails, and rubs his eyes, and yawns.
He's SO tired. And he's only eaten today at 6am, 11am, and 3.30pm. I've been pumping a bit cos of engorgement, so I think he's eating a bit less than usual. At nursery yesterday he only ate 3/4 of his bottles, too.
I know we're supposed to trust the boob, and trust that yes, they ARE hungry when they say so, and I've always fed on cue - so am I supposed to trust the refusal? Is he just not that fussed about food and will it pass?
It feels oddly personal and rejecting, when he rejects the breast. Specially at 4am when he's woken and won't let me feed him to settle, and instead cries cos he's so tired. 
I've been marching him around our v. small flat in a sling, then crying and getting DH to do it as he'll settle better with him - but this can't go on. What on earth is happening?