I came across plethoric while using an online thesaurus and it piqued my interest. Yes, this word related to plethora can be used to to describe any feeling of excess or overabundance. Here are some examples:
The occasional use of these medicines seldom fails to prove highly beneficial to the plethoric, bilious, and dyspeptic.
Located in eastern Siberia, Kamchatka is a little-visited and pristine wilderness area, home to many active volcanoes and plethoric wildlife.
Now, the next time you have a Thanksgiving, Christmas or otherwise Feast of Maximum Occupancy, you can put your word power to use and LJ "Today's dinner at Grandma's turned me into a plethoric mess--but in a good way!" :-D