While playing Pokémon GO at SeaWorld, I tried to catch some Pokémon. Out of the 20 or so, all of them fled! Also, it wouldn’t let me spin Pokéstops. I had WiFi, GPS, and 5G Lte, so why couldn’t I catch?
You were probably soft banned for a limited time.
Were you spoofing? Or had anyone opened your account and spun a stop/ caught a Pokemon in another country or something? If that's the case you were on what's known as "Cool down" in the spoofing community. That is a common explanation having exactly the same effects as the ones you experienced.