Don't panic, do as the vet has suggested. I think I would do the same as you and try and keep his routine as normal as possible. If your worried about missing something, how about setting an alarm for every hour or so, and then you could have a quick check on him, however I'm sure your Mummy instinct will kick in and you would hear him being sick. (it was amazing how many times I woke in the night, just before a poorly child appeared at the bedside
)
Sending
and healing wishes to your poorly pup, and I hope its not too long a night for you.