What can cps do to me if i tested positive for marijuana during my labor?

Long story short there was a death in my family that caused me a great deal of stress when I was 8 months pregnant so I smoked some marijuana to help with my loss. I used to smoke marijuana and cigarettes everyday before I was pregnant and quit doing it during my pregnancy until that one time. I went into labor and they said I tested positive for marijuana and tested my son and he came out negative. I was interviewed by a hospital employee who informed me that she has to report this to cps. They told me for me to be able to breastfeed I would have to pump and dump for about 5 days or so which I've been doing. Its been about 5 days since I delivered my son and I haven't heard anything. Does anyone know the laws in California about cps and my situation. One of the nurses told me not to worry cause they wont pursue such a small issue but I'm still nervous. Does anyone know what the laws are in California about this situation? Or does anyone know of a website that has info about stuff like this.