JavaFX AnimationTimer not stopping properly

So, I am creating the snake game using JavaFX and I cannot seem to make the game pause properly, i.e. it pauses occasionally and other times, the game just ignores the pause. So, basically I have a Main class where I initialize all the GUI components, and it also acts as the controller for the javafx Application.

I have a Button named gameControl which starts/pauses the game, a variable Boolean pause which keeps track of the game states (new/paused/running), and the methods startGame, pauseGame.

The gameControl button's EventHandler is as follows:

gameControl.setOnClicked(event->{
    if(paused == null) startGame(); //new game
    else if(paused) continueGame(); //for paused game
    else pauseGame();               //for running game
});

The startGame function looks something like this:

void startGame(){
    paused = false;
    Snake snake = new Snake(); //the snake sprite
    //following gameLoop controls the animation of the snake
    gameLoop = new AnimationTimer(){
        @Override
        public void handle(long now){
            drawSnake(); //draws the snake on the game
            snake.move(); //move snake ahead

            //following code is for slowing down the gameLoop renders to make it easier to play
            Task<Void> sleeper = new Task<>(){
                @Override
                protected Void call() throws Exception {
                    gameLoop.stop();
                    Thread.sleep(30);
                    gameLoop.start();
                    return null;
                }
            };
            new Thread(sleeper).start();
            //force garbage collection or else throws a bunch of exceptions after a while of running.
            //not sure of the cause...
            System.gc();
        }
    };
    gameLoop.start();
}

AnimationTimer gameLoop are variables of the class to allow calling from other functions.

And the pauseGame function:

void pauseGame() {
    paused = true;
    gameLoop.stop();
}

So, as I have said before the game doesn't pause everytime I hit the gameControl button, and I suspect it is due to the Thread.sleep(30); line inside the Task of the gameLoop. That being said, I am still not fully sure and have no idea how to fix this. Any help would be appreciated.