Mine is 7 days old, and the same exact way. Last night my mother told me to try sitting her in a boppy in my bed, with a shirt that smells like me underneath it so she feels like she is in my arms, and it worked like a charm. I got 7 hours total of sleep.
I'm sure that was wonderful! That said, it is not safe to use the boppy as a sleeping prop or pillow. I thought it even said so on the tag?
My go-to for helping with newborn sleep are the 5 Ss - swaddle, shush, side, swing suck. For us that was nursing b/c she didn't like pacifiers. DD2 slept swaddled in a swing or bouncer for the first 9 months.
We have a similar system. DH does the final diaper check/change in the cosleeper while I get myself set up to nurse (Boppy set up, burp rag in place, boob out). Then, as soon as she's swaddled, because she kind of fights it sometimes, DH hands her right to me and I immediately put her on the boob for her last feeding. She seems to forget about the swaddle as soon as she tastes the milk, and almost always falls asleep while nursing. You just have to make sure if your LO NTS, they're coming off the boob once they fall asleep. If they're still awake aft nursing, you could try a pacifier, but only if your LO has a good latch while feeding. DD was given one I the hospital because she took to BF right away, but if she hadn't, they wouldn't have given it to her.
When we are able to make this work, which is pretty often, we get a good 3-4 hour stretch before she wakes up again. But at five days old, you have to make sure you're feeding at least that often, so you may have to wake LO up. DD would usually wake herself up at that point, anyway, so you may not have issue with that.
Our pedi also recommended a rolled up blanket UNDER the sheet in order to help her feel as though there is still someone next to her. We haven't tried it yet, but that's someone you could try. The nurses also did this in the hospital, one on either side,and it helped her feel nice and cozy. They just used swaddle blankets.
Good luck. I remember being brought to tears those first few nights at home, and again once the two week growth spurt came on. It's hard, but so worth it in the end.