Does ovulation occurs after discharge.

I notice discharge only once in a month, sometimes two days in a row & sometimes it's like i get tiny discharge & then again after let's say 3 or 5 days, another tiny discharge, i know it's related to ovulation but how come i see discharge only on one day, does discharge signify start of ovulation or does it signify that ovulation is already over, i tried testing strips but it's all very confusing, i usually feel like getting intimate around the time i see discharge but what does it signify, does it mean ovulation is about to happen in next 12 to 48 hours or does it mean it's already over? Also is it possible to get pregnant at this age if i have sex only once in a month, around the time i see discharge? Is one time sex sufficient for pregnancy? I have tried five odd times last year but obviously no success.