Positive OPK

Allinasmile38 • ❤️ TTC Baby #2 ❤️

So I got a positive OPK last night and this morning of course my BBT was lower than the day before so I am assuming I will probably ovulate today. Do I need to keep taking OPK to watch the line fade away or keep track of my temperature to know the exact day I could have ovulated? How will I know the exact day?