Am I being hacked?

I just setup a 404 page to receive e-mails whenever a visitor lands on the 404 page of my site.

It has been very educational.

Random alerts when someone searched google for this or that. But this morning there have been a flood of e-mails from someone who can apparently see my theme titles and is trying to view the screenshot of each theme inside wp-contents/themes/.

He’s going to https://www.brockangelo.com/wp-content/themes/…

Funny thing is, when I go to that location, I can’t see a directory of themes uploaded – but whoever it is can see custom theme titles that I built – so he’s not only guessing the most popular themes – but he’s getting access to the directory somehow.

Should I be concerned about this? Or should this be directed to the maillists?

EDIT – I’m noticing that some of the attempts are coming from …/wp-admin/themes.php – has someone gotten into my admin panel??!!