E.R.
First off, take a deep breath, it will be all right. I have been EXACTLY where you are now and it is hard work at first, but you will get through it.
I know you love being a stay at home mom, and your kids have special needs, but you may have to make some other arrangements for a while at least. Unless your ex is going to totally support you, you need to focus on getting a job and health insurance, ASAP. I am assuming your kids' medical needs will still be covered by your ex?
There are work from home jobs you can do, but most require training. Doing medical billing could be an option, but you need to be trained and then hired for it. What options do you have for childcare? Do you have someone who comes in and helps with the kids or family you could get to do some babysitting at least for a month or so until you are back on your feet? In this economy you can't just wait for your house to sell- it might take a while.
I know it sounds crazy- but in my PERSONAL experience, you will feel better the sooner you make big adjustments and move on with your NEW life. My son and I moved into a one-bedroom apartment, but it was all ours. I worked a low paying job with no insurance until I found a better one, but we managed and I actually lost a lot of weight from my 'menial' labor, lol, so it was a huge benefit in that respect.
You are going to have to stretch yourself and be creative and think outside the box in ways you didn't have to before. It IS hard, but it can also really make you grow. Your children as well- I know having things be different will be a more difficult adjustment for them, but in the end, it might not be a bad thing as well.
Find your support network and USE it. Now is the time to do that. Go to the village and find out what community support systems you are eligible to use and take advantage of them. Do not ever feel guilty or low-class or whatever for that. Those services are often for people who are just in a temporary hard spot- whether it is child care or health care or whatever, if you need it for your children, then you just DO it.
Do a web search for home based careers. I know its hard if you've been staying at home a long time, but you may have to just knuckle down and get at least a part time job until your home sale goes through. Just make your arrangements one by one and do what you can. Don't beat yourself up - you are doing the best you can and it will ALL WORK OUT FINE.
The first year after the divorce is so hard. But it will just keep getting better and better, trust me. :) Last year I got remarried to a wonderful, kind man and now we have a house and dogs and ... let's just say I would NEVER have thought it would be possible the year after I left my husband. All sorts of things happen- and not all bad!
*hugs* hang in there and best of luck! You'll be fine!