If you are happy to live a pared-down lifestyle in order to SAH with your children, that is your choice and good luck to you.
BUT: does your DH agree? If he agrees that it's important to both of you that your children have a parent at home, and is genuinely happy to "take one for the team" by working longer hours and seeing less of your children, then go for it.
If, however, he isn't happy, then I think you are playing a very dangerous game.
Children thrive whether at home with parents or in childcare. At the end of the day, SAHPs do it for themselves, even though they'll try to tell you (and themselves) it's for the children. But it's a selfish decision if it has a negative impact on your family overall, and it's a luxury that most people in this world can't afford. Makes no difference to the children, honestly it doesn't.
So, be honest with yourself that you want to do this for yourself. If you end up losing your home because you can't pay the mortgage or insurance, your DH is resentful and exhausted of the extra work he has to do and the small amount of time he gets to spend with his family - will it all have been worth it just so that you got to do what you wanted to do?
However, it doesn't have to be all or nothing. Will your current job let you go part-time? If not, have you looked into local part-time work like your corner shop, supermarket or pub? Or, as someone else suggested, childminding works well for a lot of people as a way to SAH and still cover the bills.