HUGE hugs Anna, I remember. I discovered Riv liked to suck on my little finger for comfort, and he wouldn't have a bar of it if he was actually hungry, so there wasn't any confusion there. I think it was pretty early on (though Riv had got the hang of b/fing by then, so no confusion) that we introduced a dummy too - me, who was never going to use a dummy, discovered that it saved my sanity with a comfort sucker.
Take care of yourself too, make sure you're eating and drinking enough, a huge part of my exhaustion in the early days was giving giving giving food to a baby, and not getting enough myself. If you have to go out and blow money on frozen meals, tinned soup, easy food, do it. Whatever it takes to get through these first few weeks!
Bookmarks