The hover definition for sad also includes "trista," which my Wells dictionary does define as sad. So, what are the shades of meaning for trista (plain old sad?), malĝoja (un-joyful/un-glad?) and malfeliĉa (unhappy)?
Could you also say mi tute bedaŭras la rezulto?
That would mean you're sad/you regret. Not quite the same
But I do wonder why malfeliĉas isn't accepted