You should immediately discuss your problems with a family lawyer. I do not know if CFS in FL requires a drug test in the circumstances you posted, but children are not taken away permanently without a court hearing, but you should be co-operating with CFS not fighting them.
You might find my legal guide on selecting and hiring a lawyer helpful.
You might find my legal guide on Is it Legal? Is it Illegal? helpful.
You might find my legal guide on the understanding the different court systems helpful.
You might find my legal guide on legal terms used in litigation helpful.
(Even if you are not filing a lawsuit this information can be useful).
You might find Gabriel Cheong’s legal guide on the do and don’t of finances after a divorce helpful.
You might find my legal guide on divorce in general and in NJ helpful.
(Much of this information is valid for unmarrieds who have children together).
Mr. Sarno is licensed to practice law in NJ and NY. His response here is not legal advice and does not create an attorney/ client relationship. The response is in the form of legal education and is intended to provide general information about the matter in question. Many times the questioner may leave out details which would make the reply unsuitable. Mr. Sarno strongly advises the questioner to confer with an attorney in their own state to acquire more information.
In Florida, DCF has an obligation to protect the children even if they are wrong at the onset of the case. If they "shelter" the children (take them away from you), you are entitled to legal representation at the Shelter Hearing, DCF has a very low burden of proof at this hearing (probable cause) but at this point you are before a Judge. You will want to ask the Judge for legal represenation, which you are entitled to every step of the way. What ever you do, do not waive any legal rights. If you refuse to take a drug screen, it may automatically be counted as a positive drug screen since you refused. As soon as you can, please consult with an attorney to find out of all of your legal rights.