Convalesce is a soft-sounding word, and it describes something you should do in a soft bed: recover from an illness.
When someone is convalescing, you can be sure something bad happened to them. Maybe they were hit by a car, had a heart attack, or got a bad case of the flu. People convalesce in hospitals, or, if things are a little less serious, at home. A nursing home is sometimes called a "convalescent home," because the old people who live there often have health problems. When you're sick or hurt badly enough to be convalescing, the good news is that you're starting to heal and have time to catch up on books or TV.