Clomid. Cd 18

Ashleigh • Engaged to my best friend and soldier. We have a 5 year old son, and currently ttc our second ❤️
I took clomid 50mg days 5-9. Im currently on cd18 and still have yet to get a positive opk. It's light like almost there but not quite yet. It's been the same yesterday and today. When should I look to ovulate?