Is there any way to appeal a federal court decision involving custody. Can the children themselves appeal?

All allegations were disproved, i used to smoke marijuana and because my body was still dumping THC, the judge took one look at it & decided I was unfit, both children are excelling at school, are happy and settled. The impartial childens advocate was referring to me in general conversation as "the junkie" even though I dont use any hard drugs. The judge discounted all the reports proving that the children are happy & normal & settled. All he saw was the pot. I had a long term marijuana habit thanks to the childrens father selling it & bringing it into my life. I used it as a crutch to get through a nervous breakdown but went to my doctor to ask for help & he put me on valium 2mg & efexor-xr, The valium is just until the efexor kicks in. The judge flew into a rage and decided before hearing any evidence that I am unfit the second he saw my drug test which only showed the prescription drugs i was on & the remnants of my body dumping the THC. It was in federal court. What can I do now?