Hello Mateusz,
Have you tried to use a different mouse?
It can be caused by mouse/hardware issue or settings issue. So I recommend that you follow the troubleshooting steps:
Try to restore the defaults.
Press Windows + E buttons together on your keyboard
Move to View tab on the top
Tap on Options - Click on Change folder and Search options
Tap on Restore Defaults. Then press Apply and ok
Alternatively try to change the Mouse settings.
Tap on the Settings icon from the start menu
Tap on Devices - Click on Mouse on the left pane
Tap on Additional Mouse Options on the right pane
You will open the Mouse Properties window, then move to Buttons tab
When you are under the Double click speed, drag the slider to the left to slow down the double click speed.
Disable pointer precision to slow down the mouse. Go to Pointer options tab, and uncheck the Enhance Pointer Precision .
If you need more information, follow the steps from the article on Windows 10 mouse has started double clicking on single click randomly https://answers.microsoft.com/en-us/insider/for...
Post me back, if you need further assistance.