A grave illness in a dream is traditionally read as something in your life that feels out of balance, not as a sign about the body. Dream books see it as worry, exhaustion or a feeling that needs attention.
When this appeared in your dream, what were you feeling?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.