hi. i feel for you! i breast fed both mine until 15mths. my 2nd was fine but my 1st was a hungry baby. at 4mths she was on me every half hr for half hr. the hv said to carry on but i introduced rice at 4+1/2mths. i even developed a sore on my bum!! that was it, time to move to solids!!
stick it out as long as you can. it is well worth it. you could try what jac says but it's if you have the cash for that. i expressed with my first so huby could give me a short break. but when he's a work it's not really much help. although you could try giving the bottle as they do drink quicker from it, i found anyway, so that may free you up a bit more.
when you go out don't be afraid to feed him. find a baby breast fed friendly cafe. they are out there. if you can't feed in public, sorry but don't go to town for a while. he's cries for a reason and it's upto you to feed him. it won't be long before you can introduce solids if you wish. stick it out.
i think how often he's waking is pretty good. he will wake more often for a feed as he starts getting to the 4mth age as he's getting even hungrier! after around 6-7mth, that's when i'd say it would be habit waking and not hunger, then you'd have to start and cut the night feeds out. untill then it's very hard work i'm afraid.
drink plenty of water as feeding makes you tired. more he feeds, worse you'll get.
you say he's a lovely baby so he must be happy and satisfied so keep at it. go to the library and get some books to read while you feed. ignore the house and stuff you need to do. concentrate on your baby cos he'll grow so quick you'll miss it!!