I tend to agree with the other mom's. I would do the following in this order:
1. Call your school and see if there is any way to delay and/or reduce payment. Many schools have some buffer and have assistance ready for those who need it.
2. Try to find a short term job that will provide income (e.g. starbucks, kelly temps, manpower, mcdonald's, etc.)
3. If you still need help, ask your church, a family member or close friend... put your agreement/terms in writing... no matter how close you are. This could be sticky... but depending on the resources of your friends or family... they may not mind at all as long as you pay back when you say you will.
4. Go to a lender... I would only go to a reputable financial banking institution... ah... the irony of those words. Basically, go to where you have a savings and checking account... someplace like citibank or wells fargo or navy federal credit union.. a banking institution will also offer small loans and usually do so with much more reputable terms and interest rates.
5. As you are doing the above, reflect on the cost of your son's schooling and other expenses (especially miscellaneous one) and your income source and think about whether the private school is worth the money... or would public be just as good. (Not sure how old your son is:))
Best of luck to you and hang in there. Focus on the core important things and you will be provided for.