It's possible that only you (or a very small number of people) were affected. Remember that Fastmail reported a network connection problem between some racks the previous day. I wonder if your problem is related.
Fastmail also uses the automated Pingdom system to keep track of remote connection problems:
http://stats.pingdom.com/w17m1yxzjyin
Of course, it's hard to completely automate status pages.
Bill