The fairy tale Cinderella gives us many examples of uses for the word wretched. Poor Cinderella had a wretched childhood, living in wretched conditions with a wretched stepmother. It would be enough to make anyone feel wretched, or absolutely terrible.
Wretched is an all-around unhappy word. If you're very ill, heartbroken, or riddled with guilt, you may feel wretched. This word is also used to describe awful living conditions. If your cabin at sleep-away camp is freezing cold and rat-infested, you could describe it as wretched. And if you truly don't like someone, you might call that person wretched — though maybe not to his or her face.