The scary thing in this situation is that you are the only income for your house. Personally if it were me, my first thought after reading this is to work part-time at your lawn business at least one more year. It sucks trying to tough out both jobs I know but you have to provide for your house. But tough it out and try to squeeze in as much business as you can next year and pick up new customers and see how well the year goes for you and how good you become at holding onto customers. And to me the important thing over this winter and all next year is save any and ALL extra money. Stop any spending that is not absolutely necessary. I am not saying that you are not smart with your money, but there is always areas to save more money in. Stop going out to eat, get rid of the frivolous things and put every single extra penny back. That way when you do go full time and go through a rough patch you will have a reserve of funds.
But that's just my two cents! I hope everything works out for you though, good luck.