While it is possible that the stain you saw on the
bedikah cloth was indeed caused by the hormonal fluctuation of ovulation, it still may invalidate the
clean days, since ovulation bleeding is
uterine blood. Women who regularly experience ovulation bleeding that interrupts the clean days should consult with a rabbi or yoetzet for further guidance on successfully completing the clean days.
Be sure to bring the stain for
evaluation, since often what may seem clearly red at first glance, may lighten/darken/change shade and may not actually be a problematic stain.
Please feel free to get back to us with any further questions.
B'Hatzlacha!