One of the biggest symptoms to look out for is a depressed mood or loss of interest or pleasure.
Most importantly: keep yourself calm and controlled! A child looks at his/her parent's reaction to determine the degree of threat. If he/she sees that you are clearly upset, emotional and crying, he/she will respond accordingly. Try to stay calm, relaxed and friendly when you and your child separate, it will automatically make him/her feel more calm and safe.
Play therapy is defined as a psycho-therapeutic technique whereby the therapist attempts to give the child the opportunity to express his or her feelings verbally and non-verbally. Simply put, a therapist attempts to create a safe environment for a child to express their feelings, through ways that are understandable to a child.