Should I stop breastfeeding until my cracked, scabbed nipples heal?

No. I would try to increase the spacing between feeding somewhat, be sure the latch is good, and put something like lanolin on your breasts.
No. Cracked scabbed nipples may mean a poor latch. If there is a lactation consultant in your area, seek her out. You may have to shorten nursing and pump a little. Also express a little milk at the end of nursing and put that on your nipples. It is rich in antibodies and growth factors and helps them heal your baby may also spit up red blood from nursing and getting your nipples to bleed. That is ok!