Vaginal suppositories like this are often started just before delivery to lower the amount of bacteria or yeast in the vaginal canal, even when you have no symptoms, since that can reduce infection risk for you and the baby during birth. It's a preventive step your doctor is taking, not a sign something is wrong.
Next Steps
Suppository residue is usually whitish or creamy, stays near the vulva, and shows up within an hour or so of inserting it. True amniotic fluid is clear and watery, often a sudden gush or a steady trickle, and isn't tied to when you used the suppository.
Health Tips
Frequent urination shouldn't meaningfully reduce how well it works, since it acts locally. If you're ever unsure whether what you're noticing is fluid leakage this close to term, please see your obstetrician right away.