Things have just not been going right for you and it has caused detrimental things to occur in your life. This does not mean that you will actually have bad luck though if you merely break the glass in a dream. For the actual superstition to work you have to physically break the mirror in real life. This dream symbol is just more of an indication of what has been on your mind recently. You haven’t been able to get beyond the fact that things just haven’t been going well for you and you think it has something to do with bad luck. Think that you have had bad luck lately? Perhaps it is because you broke a mirror in real life. If you broke a mirror in real life, this would be just as good a reason to dream of breaking a mirror in the dream world too, just so that you are aware of that.
If you dream that you break a mirror just by looking at it or that there is a broken mirror on the ground after you looked into it then this suggests that you have major self esteem problems. These are issues that everyone must face and deal with in their own way. Each person has a self perception of themselves that may not fit the way that the rest of the world sees them and if you perceive yourself as generally less attractive than those around you then this might be the reason that you are seeing yourself breaking mirrors in your dreams.
Try to increase your self esteem by hanging out with people that you believe to be generally around your level of attractiveness. This will further put things into perspective for you and allow people to see your beauty as compared to others. If you have not actually gotten any insults directed at you though, or don’t have any evidence that people find you unattractive, then stop perceiving yourself that way, that behaviors is just silly. There is no reason to think that you are ugly unless someone tells you so, and even if they do, then that is just one man’s opinion.
Alternatively dreaming of a broken mirror could mean that you have gotten past that phase of your life where you find yourself unattractive. It could symbolize the fact that you do not feel as if you need the approval of others. You are ignoring critiques of your attractiveness and ignoring self image and just trying to let the world see you as how you want them to and see yourself as how you want to see yourself without that being tainted by the mirror. You are not a character in snow white; you do not need a mirror to tell you that you are beautiful. You just know that you are.