Aw, poor little guy
It really depends on the infection as to how long it takes to clear up, mate. Sorry can't be more helpful. Natty's ears were badly infected last year and it took a week and a half for them to start to clear, two courses of ABs. She was miserable for the first 3-4 days, then started to get better. She wasn't totally herself until the infection started to clear. The Dr told me to keep up the pain relief because ear infections do hurt. Natty hated having the meds too, and the Dr suggested neurofen because you don't have to give it as often.
Yeah, I would say it is totally normal for him to be ok one minute and whingey the next - he can't communicate his discomfort in any other way. And once the panadol starts wearing off he'd get sore again. IRT the night time restlessness, I've heard that lying down can make it worse for some kids (though Natty didn't have that problem fortunately for us. She was only miserable during the day) so that might be why he's fussy during the night.
I really hope he is better and that you all get some rest very soon.