I just checked my local Bitcoin-Qt wallet and saw that there was a transaction not done by me...is it possible someone hacked my computer and did that?

If so...there's nothing I can do to undone it huh.

Transaction ID is 23074af6a53af7461ab64ff5f2f25d19f15d2585107195a2b2b5e89c6f1a8f66

Address is 13SWCCtAahLnJnps3MfuW6z8ShJhSnpb9V

Can be seen at https://blockchain.info/address/13SWCCtAahLnJnps3MfuW6z8ShJhSnpb9V

Help!! I'm so sad =(