All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
We fear that you may be suffering some sort of Waswaas (obsessive whisperings). Therefore, we would like to warn you against getting caught up in such Waswaas, because it causes much harm.
It is quite simple and plain; this vaginal discharge, also known as vaginal moistness, invalidates the Wudhoo’. However, the discharges are ritually pure and therefore it is not incumbent on the woman to be precautious about them.
Whenever a woman doubts there being a discharge, she should act in accordance to the presumption that no discharge has exited unless she is certain that one has. Certainty is only overridden by certainty (not doubt or suspicion).
No matter how much you suspect that there is a discharge, you should simply ignore such suspicion until you are certain. You are not obliged to check, investigate, or look to make sure if there was a discharge or not. If you become certain that there was a discharge, then you are obliged to perform Wudhoo’. If you are doubtful about the exact time of discharge, you should estimate the most recent time when it most likely exited.
Allaah Knows best.