If you've done something so much that it doesn't excite you anymore but just leaves you tired, consider yourself jaded. If someone says you look a little jaded, it just means that you look tired.
The history of jaded is not clear, but perhaps it is related to the noun jade, an old term for a worn-out horse. Even if not, picturing a tired old horse may be a nice way to remember that jaded means dulled or tired from too much of something. The word can also mean cynical because of bad experiences with something, like a jaded journalist who doesn't see the person behind the politician.