I am 14 weeks today! I was on P4 until 12 weeks, which was actually longer than my RE wanted. She said I could stop around 9-10 weeks, but I just wasn't comfortable doing that. Also, I had the endometrin and since it was so expensive, I planned on finishing it! I weaned myself down to one a day starting at 11 weeks and took my last dose at 12w1d.
Also, RE's and OB's have different views on P4 too. My OB was on board with what my RE was supplementing with, but when it came time to stop and I asked her if we could test what my levels are now that I'm done, she said it isn't necessary since the placenta has taken over. I'm really trying to trust in my body and my OB that my P4 is where it should be now, but I have no idea and the not knowing is somewhat difficult.
It is so hard not to compare and to constantly wonder about these levels. I also think P4 levels are generally on the lower side of normal for natural pregnancies. The fact that you have an RE that is working with you to keep you feeling comfortable is so important, so that is really great.
I also have never been on P4 support previously, and like you, also never had a reason for my losses. I was also on E2 support for the first 9 weeks. My first RE never thought either of these were factors, but I can't help but to think he may be wrong, since my next RE thought it was important. I so hope this is your sticky bean, Teresa!!!