I always laugh when childless people suggest that by around 6 months your baby should be in a nice routine and you should be getting plenty of sleep. That is when everything goes pear shapes. They start getting teeth, they have growth spurts, their diet changes, they can roll and pull themselves up, and their sleep requirements change and you just have to work out a whole new routine.
You aren't alone. Every time there is a disruption of any kind in their little lives it can disrupt their sleep. DS1 is 2 and mostly sleeps well, but visitors or weather changes, a new room or missing his daytime sleep all throw bedtime out of whack. It seems so much worse when you have gotten used to getting more sleep again too!

Have you tried a dummy rather than feeding? It sounds like it might be just sucking that he wants rather than food. I know they can be hard to get rid of later, but you could send DH in some of the time to settle DS and get some more sleep yourself.