My Son (3) And Daughter( 15months) Have Pinworms. I Gave

My son (3) and daughter( 15months) have pinworms. I gave them Reese meds three days ago and they still have worms around their butts at night. (Not as bad). But I'm worried the med isn't working on them? I took them to the doc and they prescribed me big old horse pills for them so I got them Reese instead. Should I wait a few more days to see if Reese will work? Or should I take them back to the clinic? I can't even sleep. Im so stressed about this infestation. I washed our sheets and blankets. I change out the sheets every night. I clean the toilets after every use. Wash our hands constantly. I'm so frustrated. Please someone help me!