I feel that I must state again and again to some practitioners that having a magical circle is not absolutely necessary when conducting ritual. It is but one of many practices that can be employed, but is not by any means the end all be all of Pagan worship.
The circle, by which I mean the holy space that is used to channel the energies of the divine is within each and every one of us. Having a physical marker has no power unless we give it that power, but by us simply being of the Divine we are granted some of its potent energy. It all rests within the confined yet vast expanses of the mind, depending upon our worldly outlook we may shackle or set our spirits free to whatever belief attempts to restrain us.
Unless it is your choice, do not let a layer of salt, a circle of stones or a weave of ribbons determine your level of protection, for you are always protected. Have that certainty and etch it into your very being so that you never feel compelled to look outward for gratification, but in the mirror.