That's not what draining means.
It may mean having to go to bed very early because you're all used up. The effects varies alot though.
It's not a preference.
Draining has no rigorous meaning at all, and the reader can interpret it however they damn well feel like.
I am sure that the vast majority of people have had at least one day where social duties overwhelmed them. Extroverts, meaning people who are never ever drained by social interaction (for whichever meaning drained is given) seem to be vanishingly rare.
Enjoy socialising but after a party you're glad to put your feet up and read a book? Get slight anxiety making small talk with strangers, to the point where you feel bad if you do it for more than six hours? Don't want to hang out with your boss at the mandatory company event on the weekend when you could be with your husband and kids? Congratulations, you're A) perfectly normal and B) an introvert, sort of, if you squint!
The problem is not that I don't get what it's like to feel drained, it's that I'm pretty sure everyone I hang out with except for literally one single person feels drained by social interaction at some point.