1.Similar to an actual hangover, a Twilight hangover is the feeling a person has when they wake up after falling asleep reading twilight, new moon, eclipse, breaking dawn or even the rough draft of midnight sun.
2.Also like an actual hangover feelings of regret may occur. One may notice that they have no memory of anything of the previous night,or their only memory was of them reading until their eyes started to burn.

When you eat dirt for the first time and leave your family to build a shack in the woods

When you feel depressed or lonely after seeing the movie Twilight because you are single or you want to have a romantic relationship with one of the characters so badly that it makes you depressed.