Pregnancy and drug addiction. Need an educated answer. Please help.?

I am 17 years old and approximately 10 weeks pregnant. I told my mom, but I have not been to the doctor yet. For about 3 years I have been addicted to roxy 30s. When I found out I was pregnant, the baby's health became a huge concern because of this. My mom is planning to schedule my appointment at Generations obgyn, but she does not know about my drug use. I have done plenty of research and have found that doctors will typically tell you to continue doing the drug until they can prescribe you something to get you off of it because the withdrawal can cause miscarriage. This doesn't seem quite right to me. Also, I am very worried that once I tell them about my problem they will try to take my baby away from me once it is born. I admit that I need help getting off of pills, and I know that I want to quit for me but even more for my baby so that he or she can have a healthy life. Please help with this. Should I chance miscarriage from withdrawal now and go to the doctor clean, or should I continue to do them until the doctor can prescribe me something? And even if I successfully get off of them with the help of my doctor during pregnancy, will they still take my baby away once it is born?