How to find out if my Skype account has been hacked

The other day I logged into Skype from my home computer instead of the one I usually use to log onto. I received a message saying that "MY USER has failed" twice, but I was correctly logged on...I don't know what to think of this. I have a feeling that my Skype account has been hacked into, I have never received that message before. How can I tell if someone has been creeping around in my account?