'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
Giving meaning to words has so much power. My advice is if you ever reach this point, just keep saying you love them. Just like how saying hate can become a habit, so can saying love. Before you know it, you'll feel it in every bone. Even when you're angry, you'll feel the love behind the anger, and it will help temper your reaction.