Hi mama! Clear stretchy mucus on CD18 is usually a good sign you're getting close to ovulation, tapi untuk confirm positive OPK kena tengok the actual test line lah, kalau test line sama dark or darker than the control line, baru count as positive, if not yet then you're in the fertile window still so just keep testing! A few of us here time it by checking both the mucus and doing OPK together, so both signs together is more reliable, and since you have that clear mucus already best to keep BD-ing these next few days to be safe