Hope it doesn't sound like a silly question.

Context: My cat is not the most affectionate cat in the world. But sometimes she comes to search for love and to play.  When I pet her, obviously, she likes it and starts purring. She is the loudest cat that I have ever heard purring and she will not stop for like fifteen minutes.


I'm worried she's getting tired of purring so long and she's only purring because I am petting her. Or maybe she wants to sleep (she goes numb when I pet her), but can't because she is purring.