Yep, all the PP are right on! My DS, 6.5 mo doesn't sleep through the night, and I really don't expect that he will for a long long time.
He nurses one breast per session usually, always has and is certainly thriving in the weight department.
He also began waking more frequently around 4 months. It's beginning to settle down now, but it really depends on the night, and how the teeth are feeling.
He also did the nipple chewing thing when he began teething. He now has 2 teeth and very sweetly unlatches and chews his blanket during nursing. He's only bit once and I didn't like it!
So, you don't need to worry, sounds like your LO is "normal", you are BF correctly and those people whose babies sleep through the night...whatever. Your baby needs you in the night and that's not a bad thing.
Most days I take one nap with my DS, and I go to bed around 8 or 9, getting up between 5 and 6. I think I get more rest now than when I was pregnant.