What got you was the clocks going back an hour.
![Smile [:)]](/FSM/CS/emoticons/icon_smile.gif)
For flood control it looks up when you last posted and checks the time difference. Well if you had last posted at 1:45 am and then came back 30 minutes later and posted, it wouldn't have let you. Although 30 minutes had elapsed, due to falling back an hour, it was 1:15 am. So until the time difference was > 30 seconds, you wouldn't have been able to post. You would have had to wait until 1:45 am again. Does that make sense?
Flood control doesn't apply to administrators so it didn't affect me and so I didn't notice. I have a feeling you weren't the only person which this happened to.