[tor-relays] Logfile: Tor overloaded or attacked

Hello all, I just got the following in my tor logfile:

[warn] Your Guard GrmmlLitavis ($8C00FA7369A7A308F6A137600F0FA07990D9D451) is failing a very large amount of circuits. Most likely this means the Tor network is overloaded, but it could also mean an attack against you or potentially the guard itself. Success counts are 105/214. Use counts are 71/74. 194 circuits completed, 9 were unusable, 80 collapsed, and 9 timed out. For reference, your timeout cutoff is 60 seconds.

Any idea what it really means - is Tor really overloaded or anyone aware of attacks; anything special I could or should do?