A Stranger Logged into My Other Yahoo Account From Indonesia, Help?

This is what the e-mail states...

"We noticed a login to your Yahoo! account (kishling) from an unrecognized device on Mon, Sep 9, 2013 7:38 PM WIT from Indonesia."

How does this happen? I never give out my password, but I bought several things with an Amazon account linked to that e-mail account. I use the Walmart MoneyCard to purchase things. I haven't been on my other e-mail account for a few weeks now, and I usually my other older one. I got this e-mail like last week, and I wasn't online for over a week.

So what's going on? Should I be pretty worried...?

Anonymous2013-09-17T06:15:56Z

Favorite Answer

first thing to do is change your password.
how to do so.
http://help.yahoo.com/kb/index?locale=en_US&y=PROD_ACCT&page=content&id=SLN2035

http://voices.yahoo.com/protect-accounts-getting-hacked-10827849.html
how to protect your accounts.