Our youngest dd was diagnosed at 2 weeks with reflux

She was (and still is at 2 1/2) a horrible sleeper. She needed to be propped up to get small amounts of sleep, so we also did what worked. She slept in her boppy mostly (between dh and I) and she also slept some in the swing beside my bed, in her infant car seat, and in her bouncy seat. It was just horrible in those early months. She still never sleeps through the night- unfortunately I think some of it is habit by now- but it is better than it was. We did what we had to do to get some sleep just as pp said. I know it is not what is recommended, just what worked for us.
Im surprised that at 6 days old your baby is so mobile. Hopefully he will settle down soon and you all can get some rest. Good luck to you