You are a 疲れ (tired) 様 (honorific that kind of refers to whoever's being mentioned with this word). You say this to people after a day of hard work or after a good practice, etc. お疲れ様でした! I suppose the assumption here is that everyone worked until they were tired, so it was a good work, and then you thank them for it and mention how tired everyone is.
Kyoko(Tokyo accent, female)
Kenichi(Tokyo accent, male)
The reading comes from 疲れ and 様, combined together into one word.