I got my server working properly and even added jumping but how do I make UI hide when looking away?

Unity Engine
1

Here is what I have so far!

How do I make the HealthBars hide when the camera is facing away?
Can you see in the video how they are floating all over the place looking horrible?

2

Fixed GUI issue with this

void OnGUI()
    {
        InitStyles();

        // Draw a Health Bar
        //   Vector3 pos = Camera.main.WorldToScreenPoint(transform.position);
       
        Vector3 pos = Camera.main.WorldToScreenPoint(transform.position);
        if (Vector3.Angle(Camera.main.transform.forward, transform.position - Camera.main.transform.position) < 60)
        {
            // draw health bar background
            GUI.color = Color.grey;
            GUI.backgroundColor = Color.grey;
            GUI.Box(new Rect(pos.x - 26, Screen.height - pos.y + 20, Combat.maxHealth / 2, 7), ".", backStyle);

            // draw health bar amount
            GUI.color = Color.green;
            GUI.backgroundColor = Color.green;
            GUI.Box(new Rect(pos.x - 25, Screen.height - pos.y + 21, combat.health / 2, 5), ".", healthStyle);
        }
    }