Spotting at 9dpo???

Hi everyone! Hubs and I have been ttc for years now. I’ve been diagnosed with low progesterone, pcos and secondary infertility 😒 so the odds are against us. We have tried clomid and progesterone - neither has produced baby! Anyway, this was my second month on 2000mg metformin (I’ve been on 1000mg for 1.5 yrs) and I FINALLY got a positive ovulation test on day 16. I’m 9 dpo now and have had some very light spotting this afternoon/evening. Not enough to hit my undies but enough to see with every wipe. It’s lightened up even more now, barely visible. It began as light pink and ended more brownish. I’m beginning to feel a little crampy but am praying it’s not AF 5 days early 😔 Took a frer this evening and it was negative.

Have any of you experienced this type of bleeding, ending with bfp??? Thanks for any advice ;)