Spotting before ovulation TMI

Usually ovulate between day 18-24.... last month had a chemical. My cycle is 33-35 days.

tracking ovulation. Today I'm cycle day 15, but still low fertility on both tests..... I definitely have not ovulated yet.

Sorry TMI but....Started spotting brown today. First was a brown clot... then later just a small amount. Now nothing.

Was hoping I was going to ovulate next week, now no clue what's going on.

Have any of u experienced this or heard about this happening? What could be going on? I'm 38 and had 2 successful pregnancies but this never happened, ever.