OP, I am sorry to hear your husband acts this way and may be laid off. However that doesn't excuse his comment about only working 3 days a week. We all know the housework, bills, errands and childcare don't stop. Unless you have a private accountant, chef, nanny and cleaning lady, then it is also considered work. Does he think all you do on your days off are spent lying on the couch eating bon-bons watching the young and the restless? Of course you don't! He needs to realize that 1) 12 hr shifts are longer than that and physically draining, and 2) your days off are still spent on other work. Marriage and raising a family are a team effort. It's not fair for you to work on all of that.
As far as money problems go, I suggest you and DH read Dave Ramsey's "Total Money Makeover." It is an excellent book for re-evaluating spending/sticking to a budget, getting out of debt, planning for financical emergencies and saving money. Both partners must be on board for the plan to work. Perhaps if your husband felt a little more secure with the finances he wouldn't act like you should be killing yourself in OT at the hospital.
My DH used to be a hospital nurse and worked 12hr shifts, but he's been in home care management the last few years. I've heard that "only work 3 days a week" come out of his mouth a few times and I want to bonk him in the head to jar his memory!!! I get up at 5am, home at 8pm to a 3yr old who still needs to be put to bed and a sink full of dishes. He wants to "unwind" from his 9-5 office job, well I want my time to unwind from my pager and running to rapid response calls! We've had a few heart to hearts about the division of labor and we are making progress. Plus we read the Dave Ramsey book and started the program, which I think will also help decrease the stress. Good luck to you!!