After visiting the United States for six months, do I then have to be away from the United States for six months before I return again?

No. In theory you can leave the United States and then come right back in for another six months. However, the immigration officer may wonder how you are surviving without work in the USA and whether in fact you are living there illegally. It is a judgment call at the border on this matter. If you have strong roots in your home country that suggest you will return there, you will be more likely to be granted a new visitor's visa.