I've been in your shoes. My husband and I both agreed that staying home with our kids is the way to go but its a really hard thing to stick to once the bills start rolling in and you have no money to pay them.
What sort of hours does your husband work? Have you thought about looking for a part time evening job so that you can work when your husband is available to look after the kids? This has the added bonus of making your husband VERY aware of how much a$$ sitting you have been doing while staying at home with the kids.
Also...if you have the personality for it there are a lot of good companies that make it possible to work from home. My sister works for a cosmetic company and brings in an extra $1000 a month for her family without having to pay for a sitter very often since she works around her husbands schedule. I don't really know if I'm allowed to say company names here so I won't...and it doesn't even have to be cosmetics, there are lots of companies out there. This is also a great way to meet other women in the same position as you and you can often trade babysitting when your husband isn't available to watch the kids and you have to work.
Or you could try putting up a flyer at your local grocery store offering house cleaning (working around your husbands schedule) or baby sitting in your home (you're already working there anyway).
Also..something that my husband and I found very hard to do but it really made a huge difference...is you have to sit down and agree on what you are paying and what is waiting. Most of our problems came from NOT talking about what was going on and how we were going to deal with it. It takes a big effort to do it at first and its hard to not just end up yelling but once you agree on where you are at there will be a lot less tension.
Just remember that all this will pass. I really like Wayne Dyer and his ideas on abundance so you may want to check your library to see if they have or can get any of his books. Or he does have a website http://www.drwaynedyer.com/home/index.cfm
Sometimes all it takes to change your circumstances is to change your attitude. I know thats hard to do when you feel like you are drowning but it really made a difference for me when I started to look at things as something we were moving through rather than something we were stuck in. And it helps to look at what you DO have rather than what you DON'T have. At one point in time I was keeping a list of things I was grateful for and I actually put "I'm grateful for our $500 gas bill because it means we have heat in our house and a house to heat".
I'm sending good thoughts your way. Good luck with everything. I know how impossible everything can seem but its not concrete, you aren't stuck here forever.