guys not texting anymore after sex? 😫

Em
I slept with this guy 2 nights ago.
We were at talking stage for few months everyday before sleeping together.
He text me the next morning asking why I didn't send him a goodnight text after sex.
However, he hasn't replied to my snapchat or text me again since 
Concerned :(( do u think he is waiting for me to show more interest or not interested 
I swear guys always stop talking to me for a few days after sex before coming back 
Is it their way of saying they just want casual :/