Hey 428...there's nothing wrong with going inside your room and shutting the door. Or try to get your sister to take him for a few hours or so. I think your son is like 3-4 and i know all about them being attached. Does he have a favorite tv show or tape he likes to watch? I know you shouldn't use that as a "baby-sitter" but at least it gives you a break for 30 mins or so.
Also like Carl said, everything doesn't have to be done in one shot...i've been working on my son's bathroom (painting) for like 2 yrs...and i don't see an end in sight...well maybe when i lose my job, but that's another topic!
Hang in there and you got us to talk to!