hang in there B.! :D and YES! by all means, sleep when your baby does. (don't worry about the housework, thank-you notes or anything else but you & baby for a little while. all the little stuff will wait for you.)
as far as i remember... this sleep pattern is totally natural and normal. he isn't even two months yet. give yourself & him time to adjust. you're probably lucky he's sleeping as long as four hours at a time.
his belly is tiny tiny tiny & he's used to a constant food supply from the womb. he has to adjust to being fed & his belly has to grow before he will be able to go without food for too long.
color me crazy, but this is my understanding of it. i don't remember getting more than five hours of straight sleep until my baby was 12 - 16 wks.
you might try a side bed similar to the one on the link http://www.babybunk.com/. this type sleeping device really helped me. i could just feed my son & go back to sleep. since i bottle fed, my husband & i would take turns getting bottles (usually two throughout the night)... if you nurse, a side by side sleeping would really come in handy.
good luck!