A dream with a mirror suggests that you are feeling self-conscious over your image, you tend to worry about what others might think about you or how you are being perceived. It could also suggest that you are being self-critical, or are worried about your health or the thought of growing old.
To see a broken mirror implies that you are feeling emotionally unstable or there is lack of balance in your life. If you smash the mirror then you are letting go of some part of yourself, perhaps you are moving on from old ways or beliefs, or accepting yourself for who you are.
A mirror that is dirty, foggy, or difficult to see through implies that you are facing uncertainty about yourself, you feel like you don't have clear goals or purpose in life. You lack self-direction or identity.