Kelly and Soph, my DS did this a couple of weeks ago on a stinking hot day. I would have thought the heat would mean he'd drink more, but no, I couldn't get him to take it. In the end he had a huge feed after his bath in the late afternoon and then slept for 6 hours and had a great night. I hope it works out like this for you too. If your BBs are really sore I would express to relieve them. Keep the milk - you can always try EBM in a bottle if the fussiness lasts.