Newborn is feeding for 2-4 hours at a time

My 6 day old is feeding from the breast for marathons every day, at least 3 times a day. In between we'll do some feeds that last from 30-60 min but almost never less. I don't think her latch is great but when I pull her off, I see milk around her mouth and on her lips, so I know she's getting something. I know cluster feeding is real but this is getting ridiculous. My nipples are about to fall off. Any advice?