That's about the age most babies begin to wake more, if they haven't already. It sounds like you are being very responsive and loving about this new development even thought it's tougher on you!
I think you are doing the best thing by responding before he cries, I believe there's no reason to teach them they need to cry to be attended to. They give so many other cues we can read and respond to. Waiting til they cry would be like waiting til a friend shouted instead of answering when they simply spoke.
Infant sleep research actually shows that most children don't develop the ability to sleep through the night without parental help til they are about two. That's a function of the central nervous system and it just happens to take that long to mature. Some lucky parents get babies who sleep thru early on, and some parents like me get babies who wake every two to three hours the whole first 18 months!
One thing that might make his new schedule a whole lot easier on you is if you can nurse side-lying and sleep while you feed him in the night. That way you only briefly wake when he wakes and you will lose much less sleep. I recently learned to do this with my third baby, and I wish I'd learned a long time ago!