To enter a state of mental or emotional agitation because of something. You're getting worked up over nothing—I'm sure the doctor will tell you it's nothing.

What does it mean to be worked up?

: very angry, excited, or upset about something. See the full definition for worked up in the English Language Learners Dictionary.

What does get all worked up mean?

It means don't get all angry. If someone makes a rude joke then people tend to get "worked up". Simply put, you can just substitute "worked up" with angry. Ex- "John, don't get all worked up about that joke." Just replace "worked up" with angry and you get "John, don't get all angry about that joke."