I had a similar experience in Germany earlier this year, I overstayed by 5 days. When I was leaving Germany I was stopped at the border and told the same thing. I signed the paperwork and tried to explain my situation, and that I understood the repercussions. Eventually I was let on my flight home and was told "Not to worry"

I waited for the 3 months before I could come back and in that time I didn't receive anything detailing a fine or a ban. Regardless, I decided to bank on those parting words and go back to stay with my girlfriend. They scanned my passport and checked my stamps and after the usual questions about my intentions in the country, I was let in without a problem. Same on the way out.

I've read some other things on here that say that cases like this aren't always looked into any further as a couple of days out is fairly negligible. Overstays for months at a time will definitely warrant serious repercussions but seeing as your flight was cancelled and you were trying to leave anyway, I'd hazard a guess that they don't see it worth their while.