CPS is going to investigate to see whether or not your home environment is a safe one for children to be and whether your use of prescribed medications are somehow jeopardizing your children by preventing you from taking adequate care of them. Typically, until they make their investigation
, they will remove the child(ren) and place the with relatives or in foster care.
It's not possible for me to say whether they will quickly find that your children are not at risk and return them to you, or whether they will require that you cooperate with them and make some lifestyle changes in order to get your kids back. Much will depend upon their findings.
You can contact CPS if you have relatives you trust who you know will be able to temporarily care for your children until the investigation is complete, and you should find out if you are able to visit them while they are not in the household. If you can, you ought to do so.
They may want you and your husband to have drug counseling, for example. And if they require you to do these things, then cooperation with them rather than argument is best. You may already be past this point, as I see that you have a Family Court date and that they are asking for a hair follicle test. Although you can certainly hire a lawyer and try to contest this on the basis that all this is is harassment by CPS, as they already know you and your husband take prescribed medications, a judge will almost certainly order a hair follicle test. As objectionable as it may seem to you, the quickest way to get your children back is to try to work with CPS instead of arguing with them. They are a very powerful agency, and they are fond of finding ways of letting you know it that will tie you up in litigation.