When I try to zoom out of a photo, it zooms back in instantly once I release the mouse click.

Have you tried to reset the preferences as @Chuck Uebele wrote?

If no, then please try to reset the preferences of Photoshop using the steps described here:

https://helpx.adobe.com/photoshop/using/preferences.html#reset-preferences

Please backup your settings before resetting the preferences. You can check:

https://helpx.adobe.com/photoshop/using/preferences.html#backup-photoshop-preferences

 Using a mouse. On windows.

How are you zooming in? Are you using the keyboard, or a mouse? If a mouse or track pad, are you using the scrubby zoom or drawing a rectangle around the area you want to zoom into? Can you post a screen shot showing what your setting are in the main menu?

Have you tried resetting your preferences?

how to fix this?