Child Protective Services has broad authority to protect children if they believe that they are in a situation that may endanger their lives or well being. Now that stuff aside, you do have a problem. You will tell CPS that it was just stress and everything is good now. What they will hear is I'm a junkie and smoke daily. They are going to ask to test you. If you refuse then they will get a court to temporarily remove your children from your care. So you have a choice, cooperate with the test and prepare to jump through all sorts of hoops before you get CPS out of your life or refuse and prepare to have to jump through hoops anyway. If you have any kinds of means at all you should consult with a local lawyer that does this kind of law. If you don't have money ask the judge to appoint you counsel.