Toddler and a newborn who always wants to be held

I have a 3 year old son and a 5 week old son. My younger son refuses to nap anywhere but in our arms - we've tried a couple swings and lots of attempts in the crib. He'll sleep in the crib at night but not during the day. My husband goes back to work in a week or so (he works 24 hour shifts). I'm feeling really nervous about how to handle my toddler and newborn by myself. I baby wear some of the time but I've been having back issues so my body can't handle baby wearing all day. Anyone else in a similar situation? Suggestions for how to make it work??