A non-alcoholic hangover happens when someone has not eaten all day or has very foolishly consumed a large cup of coffee then taking a standard dose of dayquil, resulting in a headache that resembles a hangover.
John Doe: I have such a throbbing headache.
Jane Doe: Why?
John: I have a terrible cold and I took some medicine after I had my morning cup of coffee.
Jane: You have a non-alcoholic hangover.
John: Sure feels like one.
When you feel like crap, have a headache, and basically all other hangover "symptoms" without drinking
Paying the price of getting wasted, without drinking alcohol
Getting wasted, without getting wasted, and then having a hangover- because you partied that hard;]
Girl: I have such a bad headache, and I feel totally dead. Partied hard last night.
Friend: drank a lot huh?
Girl: No...I'm having a non-alcoholic hangover..it's pretty ugly.
"I woke up this morning with a non-alcoholic hangover...and my mom thought I had drank last night. So I'm grounded. Guess I can't be the designated driver man"