What is pending_update_count responsible for in the Telegram API?

Question

API

I decided to create a bot using MVC, everything works fine for all messages. But after a while it completely stops responding to messages as if they do not come.
I decided to drop everything on pending_update_count, because after sending any message, it increases as a result it fills up and prevents other messages from working normally.

public function index(Request $request) {
       $message = json_decode($request->getContent())->message;
   
       $command = $this->constructCommand($message->text);

                //КОМАНДЫ КОТОРЫЕ ОБЯЗАТЕЛЬНО ВЫЗОВУТ sendMessage
                switch ($command[0]) {
                    case 'start':
                        /* ДРУГОЙ МЕТОД ДРУГОГО КЛАССА*/
                        break;
                    case 'help':
                        /* ДРУГОЙ МЕТОД ДРУГОГО КЛАССА */
                        break;
                }
       }
}

private function constructCommand($command) {
       $substr = substr($command, 1);
       $exploded = explode(' ', $substr);

       $exploded[0] = explode('@', $exploded[0])[0];

       return $exploded;
}

/* ФУНКЦИЯ ОТВЕЧАЮЩАЯ ЗА ОТПРАКУ СООБЩЕНИИ */
static public function sendMessage($group_id, $message) {
        file_get_contents("https://api.telegram.org/bot".env('SECRET_TELEGRAM', null)."/sendMessage?parse_mode=markdown&chat_id=".$group_id."&text=".urlencode($message));
}

Answer 1

The problem may not be in this, again, he didn’t do anything, the bot simply stopped responding to any requests, reloading the script, everything starts working again