New to OPK testing? And bleeding?

Kristine • 26. Elementary teacher. Girl born May 18th.
I went off the pill last Wednesday, and since Sunday, I have had spotting. I'm assuming that's just from going off the pill?
Also, I have started ovulation testing, so I can get into the habit of doing it. According to the tests, I should be ovulating soon?
The top picture is from Sunday am, the middle two pictures are from yesterday (am and pm) and the bottom one is from this morning. The bottom one looks darker.