All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
The scruples that come upon a slave are in fact from the devil's insinuation and a plot against believers.
The Prophet said: "Al-Hamdu Lillah –Praise be to Allah, Who returns, the devil's plot and makes it just an insinuation." [Ahmad and Abu Daawood]
For sure, scruples and insinuations are from Satan. So, the slave has to get rid of them through forms of Thikr (mention of Allah), reading the Quran and seeking forgiveness, since the devil flees away at the time of Thikr. Moreover, when the slave seeks refuge with Allah, Satan moves away.
As for your feeling or doubt about urine dropping after answering the call of nature, we advise you to not pay any attention to that, then, consider that wetness you find on your clothes as a result of using water after answering the call nature. Thus, you can close the door of scruples.
In the same vein, a man complained to the Prophet of finding something (that may invalidate ablution and annul the prayer) while praying and asked if he should interrupt the prayer. The Prophet said: “No! (Continue in your prayer) until one hears a sound (of breaking wind) or finds (its) smell.” [Al-Bukhari and Muslim]
Allah knows best.