You cry for a reason. Other than crying because of physical pain or injury, you also cry in order to release negativity or to release yourself from an attachment when your view of reality changes.
What do you think about when you’re crying? Pay attention to your thoughts and they will lead you to the reason for your tears. If is sorrow because of a loss, accept the loss while you’re crying. If it’s desire for the past, accept that the past has happened and you live NOW.
Whatever the case, crying is a sign of attachment to the past, but it’s also the means of release from that attachment—if you pay attention to your thoughts when you’re crying. Otherwise, you can cry until you die and never get any better from it.