TTC girl, but have luteal phase spotting

I am back after successfully ttc a girl after 2 boys. I would like to sway girl again, but my cycle is so wonky lately. I am 38, so I realize my hormones are changing. After ovulation, I have brown spotting until AF starts. I asked my OB about it a year or so ago, and they did an u/s and found nothing abnormal. I have read some online and feel it is low progesterone. I am wondering if anyone has the same problem and if they have conceived successfully? I worry about m/c. I don't know much out low progesterone and conceiving, but at this point, I feel like conceiving at all would be a success.

You're having spotting all the way from O to AF starting???

How many days is your LP in total??

We may need a second opinion here because that much spotting is not ok.