T.A.
When babies are that young it is not uncommon for them to revert back the the basics some times. If you son has just reciently been sick then he still may not have his appitite in full gear. I would not force him to eat more than what he is ready. One thing I would recomend, because I have been in your shoes, is try feeding him something before bed. Not something really solid but like a milk and baby cereal mixture to help carry him through the night (more milk than cereal).
The unfortunate part of this story is that yes, you are going to be getting up in the middle of the night. When I needed to get up in the morning and was faced with this delema I would put my son in bed with me and also, have ready for him what I knew he would need in the middle of the night by my bed. i.e. ready to make new bottle, or cereal bottle, in your case it would be what ever you son has been needing when he wakes up.
What ever you do, just don't feed him the cereal bottle while he is laying down to sleep. You don't want to have a choking incident! I hope this helps.