I'm attempting to implement a really simple game state system, this is my first game - trying to make a Tetris clone. I'd consider myself a novice programmer at best. I've been testing it out by drawing different textures to the screen depending on the current state.

The 'Not Playing' state seems to work fine, I press Space and it changes to 'Playing', but when I press 'P' to pause or resume the game nothing happens. I tried checking current and previous keyboard states thinking it was happening to fast for me to see, but again nothing seemed to happen. If I change either the pause or resume, so they're both different, it works as intended.

I'm clearly missing something obvious, or completely lacking some know-how in regards to how update and/or the keyboard states work.

Here's what I have in my Update method at the moment:

    protected override void Update(GameTime gameTime)
    {
        KeyboardState CurrentKeyboardState = Keyboard.GetState();

        // Allows the game to exit
        if (CurrentKeyboardState.IsKeyDown(Keys.Escape))
            this.Exit();

        // TODO: Add your update logic here

        if (CurrentGameState == GameStates.NotPlaying)
        {
            if (CurrentKeyboardState.IsKeyDown(Keys.Space))
                CurrentGameState = GameStates.Playing;
        }

        if (CurrentGameState == GameStates.Playing)
        {
            if (CurrentKeyboardState.IsKeyDown(Keys.P))
                CurrentGameState = GameStates.Paused;
        }

        if (CurrentGameState == GameStates.Paused)
        {
            if (CurrentKeyboardState.IsKeyDown(Keys.P))
                CurrentGameState = GameStates.Playing;
        }

        base.Update(gameTime);
    }