Hi Pat,
I just wanted to offer some encouragement to look toward the future. Even though you may not be in a position to quit your job right now, you can start the process of getting you there, and maybe in two years you will be prepared. Yes, your oldest will be starting kindergarten, but the benefits of having a SAHM don't end when a child starts school, IMO.
I mention this becasue I am currently a working M. with a 2yo and a 3yo. Before having kids, DH and I knew I would be a SAHM, but the problem was, we did nothing to prepare for that or get our fiances in order, and suddenly when I got pregnant we realized I would HAVE to continue working.
Cut to two years later when our youngest was 1yo, and we realized that we didn't have to be "stuck" with me working the rest of my life, that it wasn't too late, as long as we put a plan in place. So, we set a goal that we are constantly working toward.
We are now on a two year plan to have all our student loan debt, both our cars, and our home equity loan paid off in two years, as well as having saved up at least six months of expenses for emergency (we felt it was important to have that buffer before going to one income).
Of course I had to get a better paying job to have the income to make that happen in the meantime, but I prayed on it a lot, and even in this economy was able to find a job making 30% more than I made at my last job, and ALL that extra goes toward the debt. Once we are debt free, and no longer have the expense of day care, we will be able to manage on DH's income without changing our lifestyle (like I said we are already minimalists).
Our only hurdle will health insurance, as it is SO cheap at my job right now, and DH is self employed so doesn't have the option. We have been looking into some private pay policies, or maybe nationalized health care (which I was against for a long time, but is suddenly becoming more desirable to me) will pass and we won't have to worry at all.
Yes, my older son will be finishing kindergarten, and the younger will be about to start Pre-K by the time I quit, but I don't think it is ever too late to become a SAHM. Who knows, we might even have more kids, and working part time or working from home might also be options for me.
Also, the fact of knowing I am working toward a goal, rather than feeling stuck, makes it that much easier to leave my kids and come to work every day becasue I know I am doing it for them in the long run.