Child protective services?

im from indiana ....well to make a long story short my dad has a very vindictive girlfriend who has now called cps on me for the second time to get back at my father the first time all of the allegations were proven wrong i took a drug test ped and now just a few months later she has done it again they said everything is clear just have to take another test this time 2 which is fine i complied i do not do drugs at all but here is my question about 3 days prior to them showin up i was at my fathers and i was havin alot of pain in my knee more than usual its an old injury from an accident and he told me he had something that would help and gave me a pill he said was for pain which was fine it helped my mom had the kids for the weekend so i could stay off it but now my luck im thinkin this will show up on the test and they are goin to take my children over nothing. Can they take them if i failed that drug test??? because i am not a user at all much less a chronic user and could take another on the spot but at this point all i can think about is them showin up and snatching my babies and any input would help ease my mind thanks...