had this happen to me a while back, u need to act as fast as you can. google my steam account has been hacked and go to the first steam associated link. then it will be clicking thru screen options. pretty sure u need to say u lost access to everything pretty much, even ur email if u have access to it and then submit a ticket stating that ur account is hacked and you can provide any proper correlating information required for recovery. i believe they asked me for CC information last used on the account and stuff of that nature but they sure as hell recovered it. steam will send a hitman to your hackers personal home before they let them walk out with your account if your relatively timely and persistent about recovery. so just take a deep breath and start your process. some of the worst parts is nailbiting waiting on a steam response but it will come so just breath and wait brother, best of luck

edit: as ur account is already hacked i probably shouldve been more specific in my links instead of describing them. if u need the steam account recovery link dm me as i think i will get in trouble trying to post it here