You said that your child is sometimes sad or irritable. S/he may ask to be alone or spend a lot of time alone in his/her room. Your child may seem sad or feel bad about him/herself because of some failure. It is normal for your child to feel sad about getting bad grades or not making a sports team. If a loved one has recently died, it is normal for your child to feel upset for up to 2 months.
Warning signs that things are getting worse:
If you think your child's sadness is getting worse tell your doctor even if you have discussed this before.
Adapted in part from the American Academy of Pediatrics
(AAP) Diagnostic and Statistical Manual for Primary Care
(DSM-PC) (1996)