0 clicks today

I run a small ad campaign for my business, around £1500 per month. Generally I get 250 or so impressions a day, with an 8% CTR. It's been like this for the past 2 or 3 years.

Today, I've had 93 impressions so far, and 0 clicks. It's very strange - any suggestions what the issue might be? Could it be a reporting error on Google's end? I can't think of any reasons that my clicks would just fall to zero for a day. Getting 75% top of page rate, 50% absolute top of page, but for some reason, absolutely 0 clicks!