This is not an infection of your e-mail account. Your account has either been hacked or you computer is directly linked to the account through outlook express or a similar mail management program. First perform a full virus scan of your computer with a scanner such as MalewareBytes or AVG. Make sure you have a SINGLE active firewall(such as a router or programs such as AVG) and system internals scanner (such as TeaTimer or Tripwire). After you have removed any found infections on your computer change your e-mail account's password.
