Well, it's the house of secret sorrows. The Sun and Saturn rule the father, and the Moon rules the mother. Have you had unfortunate family experiences? Conflicts?
It really depends on the rest of the chart. This is a Q&A on a group site, and people are asking me questions here because I write astrology teaching articles. It's not MY site, and it's hard for me to answer some of these questions without a whole chart.
Sun in the 12th house can mean you will be successful in what you do, but experience disappointment. Hillary Clinton's Sun is there, and I knew she would lose the election. It can also mean your work will be behind the scenes in an institutional kind of place, a hospital, hospice, jail. Moon in 12th means you hide your emotions, try to get them out in the open more. I wish I knew what signs the Sun and Moon were in. I hope that helps a bit. You just tend to be secretive and like to be alone.