I wonder if it could be eggs causing the cramping you said you introduced eggs yesterday. Food sensitivities can cause cramping too. My son recently started waking up with cramping behind his knee and I too wondered about either potassium, calcium or magnesium being needed. Since all of those can help with cramping but after taking him to his Dr. I realized that it was more likely the ice cream he had been eating lately. We cut out the dairy again and the cramping went away.