some things to consider:
do you get health insurance through your work? if so, double coverage is invaluable, believe me. i have excellent insurance but as the only one insuring my daughter and myself, i shell out right around $6,000 for our medical expenses per year (and i have some of the best insurance of anyone i know!). as a SAHM, the money you'd spend on daycare would go straight to medical care and i know personally, for me, i spend more on health care in a year than i do on day care. so take that into account.
how's your retirement plan? do you have one? if some of your salary is going into a 401k or other retirement account and your company is matching, you need to be taking advantage of that. there will be 2 of you retiring, and unless he's stashing money away like crazy, both of you need to be contributing to your respective accounts so you do not wind up like many female senior citizens do, with very little in social security and either no retirement or more expenses than you have retirement (think widows and divorcees. my grandmother is both and has $1200 a month to live on for the rest of her life, including health care costs, food, rent, bills, necessities, etc, and that's only because she has worked since my mother, now 46, was 4).
third, day care isn't as expensive as you think. for a minimum wage job (in oregon, i don't know where you are), you're making $16,536 a year. day care is usually right around $3-5 an hour, depending on where you live. say you work full time with a half hour commute, you're spending $225/week on child care expenses, or $11,700 a year. yes, you have to factor in taxes, but chances are you will still come out ahead, either with a tax refund or by using your deductions correctly.
fourth, what happens if your husband, god forbid, should die young in an accident? in this economy, or any economy, it is difficult to re-enter the workforce, depending on what you do. for instance i work retail, so it's not going to be an issue for me if i should ever choose to stay home. however, for a nurse, that is a job that requires you to always be learning. five years might be long enough for you to be required to spend your own money on catch up courses. your employer might be willing to reimburse you, but only after a specific period of employment.
all i'm saying is, your husband has the best interests of your family in mind. men look at things logically while women look at things emotionally, and women typically do not take some of these things into account when they make decisions regarding their families. there's a balance here, there always is, and it is up to you guys and no one else to find it. perhaps you staying at home means you work from home, using a sitter for a few hours a day so you can be truly productive and thus able to give your son your full attention for most of the day. or maybe it means you work part time, so you can keep contributing to your retirement and possibly some or all of your health insurance and still have the majority of the day with your family.
good luck with your decision!