Use the nursing cream that the previous poster mentioned, it works. I have heard of something called a "nipple shield" it is a silicon protector. I think it has a hole for the nipple to go threw and the silicon is around your aeriola(sp?) a barrior between your nipple and babies mouth. Have you tried a paci? My first daughter was that way, I was her paci. No help on the sleeping threw the night, my 6.5month old wake every 3-5 hours, but she is a fast feed she is done in 5 minues, no kidding.
I had to use a nipple shield for 3 months because I had inverted nipples and it was painful every time he nursed...they completely extroverted my nipples by the time he was 4 months old and I didn't have to use them anymore...they were my lifesaver. My son didn't take a paci until about 5 months old...he did here and there but not for the night.