There truly are opportunities for working online from home but it would be wise to think of creating streams of income, whether online, off, or a combination of both. Don't think in terms of having a single employer because it's likely you will have to find a variety of clients/customers that will pay you for your efforts to replace or increase the income that was lost. What I can tell you having gone down this road myself, is that you will feel much more secure when you see that you can create an income for yourself without being held to rigid schedules and not being able to take time off when needed...particularly as a mother of four.
This is the time that you should be thinking about using your current skills for profit. Can you bake, create websites, write press releases, etc? While I don't know you, I'm sure that you have plenty of skills that will translate well into your own money making ventures. You don't have to be overly formal about it.
I know a woman who bakes very good treats from scratch and she takes a basket to a variety of local businesses to sell them to employees along with some tasty sandwiches. This may be one option for you in your neighborhood or at local businesses. Find writing assignments on sites such as Textbroker or ELance, and you may also be able to make some money right from home. I do this one myself. I am not saying that you will be able to make thousands right off the bat with Textbroker or Elance, but it's most certainly a step in the right direction and your work can lead to more jobs.
Perhaps you have a little money to start your own baby sitting service or another business from home. Without knowing your specific skills and interests, this is all I can recommend at the moment, I can't get into specifics or more opportunities.
However, I was a woman that once relied on a single income just because that's what my parents and 95% of the people around me did. I got tired of the rigid schedule and office politics. While I was still working for a single employer, I started my own businesses and quit when I was finally able to do so. I have changed things around for myself and have created several streams of income and feel MORE secure this way. Best of luck to you and your family.