I have been hacked guys!

I haven’t been active on steemit lately. So I finally decided to come back live only to see my account reputation gone down to 0! So I checked my account only to see that my steem has been transferred to one unknown account saying steem evaporated in the memo. I have no clue how I was hacked in the first place and then they have been using my account to share some phishing site of theirs. Guys just to be clear I will never share any website links on my steemit account! Never! If any of you can help me change my master key , it would be of great help.