Illness in a dream rarely predicts actual sickness -- it more often reflects vulnerability, a need for care you haven't been giving yourself, or some part of your life that's fallen out of balance. Recovering within the dream can point to a genuine return toward equilibrium already underway.
Three manner of wayes the Planets are varied or changed, by reason of their first qualities, of their Houses, and significations. - William Lilly (1602.-1681.)