I am a drug addict, I am currently in a methadone clinic ( which is safe for pregnant women) I have recently relapsed on benzodiazepines, I'm 36 weeks, I fully regret what I did and am talking with my counselor to help better myself and keep my child safe, but I am completely terrified about not knowing if the benzo's will show up in my baby system or not, because then CPS will surly be involved and I am truly trying to better my life, I don't want my newborn son OR 2 yr old daughter taken away, so my question is, how long will the benzo's stay with the unborn baby?

No you don't really care if your children are taken away or not, If you really did, you would stay on the methadone and would not be on drugs that can effect your baby. The baby can be born and have to go though drug withdraws also.

So if you really, really cared, you would not be worried about how to get around it, or if you would get caught, you would merely worry about staying off the drugs.

You don't say one word about concern for the baby on drugs in your womb, but saying it wouldn't matter anyway; your actions are what count. Regrets don't help the baby.
Time in your system varies widely and the baby is almost due, so there you are.