In dreams a house usually represents the self and the life that you are living, and sometimes your own physical 'house' ie: your body, rather than
your bricks and mortar house. If you are leaving the front door open in the dream then that suggests that you are opening yourself up and making
yourself vulnerable in some way. Only you will know what that is, have a good think about things that you have been doing and the way that you have
been relating to others in the period since the dream started - once you figure it out and start to fix it the dream will stop.
hope this helps
ETA - I suspect the two girls may actually be your spirit guides since they say that they have always watched over you - it is possible that they have
appeared in the dream to emphasise to you that this is something that needs to be dealt with asap.
edit on 11-7-2012 by skjalddis because: (no