I agree with Katherine and fdmaxey. Just had another thought. Do not confuse the two idioms, "broken up" and "cracked up". While the words broken and cracked are very similar in meaning, the two idioms are completely different. Cracked up means to make someone laugh. So "You crack me up" or "That story really cracked me up" means that you make me laugh or the story made me laugh.

I'm very upset about it. "He's broken up about his divorce." "She's really broken up about her dog's death."

It means that you're very upset about the thing you're referring to. Like you could say, "I lost that book, but I'm not broken up about it," if you're not very upset that you lost your book.