Screen changes color when object is selected

When I select an object, my scene changes color. It is a different color for different objects that I select. Sometimes blue, sometimes orange, but it makes it really hard to see what the scene actually looks like. How do I turn this off?

The orange line you see is called the selection outline.
You can en-disable it in the Gizmos panel on top of your scene view.
If you like to change the color, you can go under → Edit → Preferences → Colors → Selected outline / Selected Children outline.