This is general information and not legal advice. No attorney-client relationship is formed. This is for educational purposes only.
Given what you've shared, it's unlikely DEFACS will take your 3 year old and unborn child from you. They will likely ask you to enroll in drug treatment, and if you both do well there, they will eventually close your case.
It's important to be upfront with DEFACS workers, so it will probably go better for you if you tell them now what you've taken and why. Then, at least as long as DEFACS is involved, get off all the drugs you can. Get your own pain medication for your back.
Marijuana stays in your system ~6 weeks, but the others clear out in a day or two. If you used other drugs only ocassionaly, they may not show up in the hair follicle tests.
Of course, DEFACS can request a UA at any time.
My suggestion is you and your boyfriend contact DEFACS, tell them you would like to begin services and ask what you can do.
I hope this is helpful. I have to go off line for a while, but I will check back with you within 24 hours.
If you would like to provide more information, if you have other questions or if I can be of any further assistance, please just reply to continue.
I hope I have given you good service today. Kindly chose a rating when you are ready