You may be advertising to people who live overseas!

To find out which locations people were in when they were shown your ad and clicked to your website, go to the Locations settings in Google Ads. Switch your view from Targeting Locations to Matched Locations. If your Matched locations include a whole lot of locations that you did not target, then you have fallen prey to this particularly frustrating setting! Keep in mind you are paying Google for each of those clicks, so this is an important source of wasted budget.