Don't know what your sleeping arrangements are... but if he's in a different room than you, and you're getting up, walking across the hall into another room, feeding him, then walking back to your room --> that would be more than enough to wake me up completely!
Have you considered having him sleep in your room - you can use a crib, a co-sleeper, etc.:
http://www.askdrsears.com/html/10/t102200.asp
There are lots of ways to SAFELY share sleep so that you aren't waking up at every peep to go in and check on him (if he's right there near you, you can just look w/ your eyes and not have to get out of bed). I personally didn't sleep well when my babies were in another room (at least until they were 10+ months - at that point mine were loud, quite mobile, and I didn't worry so much about how they were doing because I could usually hear everything and knew what all the sounds meant). ;)
Don't know if that helps - just throwing it out there as one possibility.