Bread breaks along bottom
This can happen for a number of reasons. For one, the oven may have been too dry, causing the crust to harden before the bread can reach its full oven spring. Underproofed dough is a related cause. If the dough is underproofed, then it needs to rise more in the oven, which may not be possible if the crust hardens, leading to a burst along the bottom edge. Deep scores may also help.
Bread is a pale white instead of a golden brown
This is often due to an overly dry oven environment. Try adding a pan of water to the bottom, and spritzing the oven with water a couple of times during the first five minutes. If the bread breaks along the bottom, I believe this can exacerbate the problem because the bread loses much of its internal moisture through the bread instead of through the crust.
Bread does not rise
Sourdough takes a long time. It may be that all you need is patience. That said, if you warm up your loaf (maybe by rising it in a warm oven) it should rise much faster. In the worst case you forgot the yeast. In that case, it's time to knead in some bakers yeast and hope for the best.