Coming off the pill

Hi guys,
Just after a little bit of advice about coming off the pill and figuring out ovulation. I came off the pill having been on it for about 6 years, about 3 weeks ago now, and had a withdrawal bleed. Now I'm trying to figure out when I might ovulate.
Naively, I kind of hope that magically I might just have a normal cycle straight away, but logically I know it might take some time. I've been using OPKs since CD10 and have had nothing but negatives... The best I've had is a faint line that could barely be made out, the rest had nothing at all. That faint line was on CD12. On that day I also had very light rust coloured spotting which I only noticed once when I wiped. It coincided with CM that was like egg white in texture but rust coloured because of the spotting. Since then more very negative OPKs and white CM (CD15 today).
Is it possible that the spotting on CD12 was ovulation bleeding, even though I had a negative OPK? Or is it more likely that it was just normal spotting and I'm still  waiting to ovulate?
Would love to hear your thoughts, thanks in advance :)