Please help me I'm a idiot and was hacked on my steam

I have been hacked, on my email and my steam, they changed the email but on my email I can see they used it to change my original email to theirs, I have proof the acc is mine but I have no clue what to do at all, someone please help me, I don't even have money there I just have had that acc for so many years, I have so many memories in there I'm desperate.

• they added their own email via my email
• I have access to my email and have proof the acc is mine
• I changed the email password -they unfriend my friends
• I did not have the steam app -i have no clue how this could have happened