'Sense of impending doom'. It means - outside of the context of literal impending doom - that your body has noticed something very wrong but can't identify It. Doctors take it quite seriously.
Madness string 105723
You just need to keep living. Listen to the pain. It's both history teacher and fortune teller. Pain teaches us who we are. Sometimes, it's so bad, we feel like we're dying. But we can't really live 'til we've died a little, can we?