be dying of (something)
1. To be nearing death as a result of something. Is it true that Mr. Thomas is dying of lung cancer?
2. To be feeling something very intensely (hyperbolically likening the experience to dying). After my girlfriend dumped me, I thought I was dying of a broken heart.
be ˈdying of something
(informal) have a very strong feeling of something, for example hunger or boredom: We’re all dying of curiosity — come on, tell us what happened!I’m dying of thirst.