Yup I hate sleepless nights like that. We sorta go by the rule that if DS is waking up every hour (which he sometimes does) and he does it more than three times in a row, its not his normal behaviour and we usually give him a dose of panadol and a small drink of milk or water in a sippy cup.
That usually settles him for a few more hours at least. His problem usually is his teeth though, he does wake up during the night from being cold, or losing his dummy, but not every hour IYKWIM?

It totally sucks though, so I'm hearin ya!!!