If I don’t see ads, I assume Pihole is working. However I’ve been having issues lately and after tweaking settings I’ve been using various websites which tell you if your ad blacker is working. Like:
http://ads-blocker.com/testing
http://simple-adblock.com/faq/testing-your-adblocker/
Do these sites tell you if your pihole is working? The first one tells me yes, the second one just doesn’t show any ads, and the third one says I’m not blocking ads. Just curious if this works for you. Especially the third one.