How much is too much milk?

I've been feeding my 2wk old. And it seems like I'm ALWAYS feeding him. He eats and the falls asleep... wakes up 10mins later or sometimes as soon as I lay him down and cries until he can latch back on. I watch him sometimes when he's feeding and it seems like he's just using it like a pacifier. He's pooping and peeing normally, but it's really hard to do things for me when he's stuck to my nipple all day. I'm not sure if he just wants to be close to me or if he's actually hungry all the time. This is my first child, so I'm stuck. Has this happened to anyone? And I've spoke with the Doctor and she says "he's fine" gaining weight normally and growing noramlly and keeps telling me that all babies are different. Does anyone have any other advice for me?