If you have lost a lot of weight and are feeling completely stressed out then you might want to go to the Dr and get your thyroid checked and get a general checkup. it would be too bad to give up breastfeeding (which won’t be caused by a night away!) You don’t need to do anything in particular to keep up your milk supply - they feed you make milk. Is he eating much in the way of solids? If not it could help to up his solids (if he wants it) I mean this in the kindest way, but you seem to be talking yourself into the urban myth that “milk just dries up” - it doesn’t. Babies that age are veritable hoovers and they can empty a boob in 5 mins flat and then down the other one in less - it’s all normal. But get a checkup for yourself