" I had a dream that i was eating either glass or mirror (im not sure) but what are glass and mirror symbolic to?"
A mirror is self-reflection or a need to self reflect upon who you are, how you see yourself, "To thine own self be true." A broken mirror (Pieces of glass) depicts a poor or distorted self image.
Eating glass is hurting yourself, cutting yourself down with your words. God don't make junk...therefore believe you are worthy to be loved and appreciated. I also feel a sadness with this dream...are you feeling sad, depressed?
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