Click-Through Rate

Adsense ad click-through rate has dropped by 50% on all my sites. The themes of the sites are completely different. This drop started exactly on February 1st.
What I am wondering is, is it like this only for me?

AdSense and AdWords are messing things up; this always happens, it is temporary.

In my opinion, this is what happens if Google unjustly bans individually submitted ads in AdWords without just cause.

I haven’t been able to check for a while; I was on vacation. Now I am analyzing the ads that appeared and banning them. There might be an issue with the ads that appeared.