Where did my email go? ruburf18@yahoo.com. It has been my email for years, and now it does not exsist.?

I was hacked. Everyone on my list got a desperate email from me saying that I was stranded in England and needed money to get home. I know I had a hacker, but how did it happen with all of the security. Now I can not get into that account as the password has been changed and I need all of my files, pictures, etc from there.