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.
Maybe because you ran out of Pokemon. This happened to me once when I pressed a Pokemon it showed a zoomed in version of it and it didn't have any pokeball option. The way to fix this is to delete the app and redownlad it and log into you account. Hope I helped :D