To dream that you are lost symbolizes losing a sense of direction in your actual life. You might have been distracted and threading a path which takes you far away from your original goals. You are anxious and insecure with the result of events.
Alternatively, a dream of being lost may reflect an attempt to catch up and adapt to the ever-changing rules and conditions in your waking life.
If someone else is lost in your dream, it points to conflict, unresolved issues, and ill-feelings you possess for that lost person. Consider also that the lost person might be mirroring lost aspects in your personality. Try to relive and recognize those significant parts of your personality.