I agree with Curligurl in the recommendation to test MTHFR and in saying that progesterone cream tends not to be strong enough to make a difference.
I've had 6 losses within 9 cycles of trying (spaced through out the year but with time off for testing and surgery), all of them very early - before 5 weeks. I found that my MAJOR player was a septum in my uterus. A septum is dead tissue and it's usually just right where an embryo would try to implant. Based on the timing of all of mine, we all believe that all of my babies implanted on dead tissue and died from lack of nutrients. I've been through 2 surgeries to have it removed. I'd highly recommend having an HSG to make sure that the inner contour of your uterus is normally shaped with no scar tissue, septums, polyps, etc. that could interfere with pregnancy.
As for the progesterone, I've also found that my progesterone has also always been an issue. Turns out that I'm progesterone deficient. PCOS, Hashimotos, and MTHFR are all closely related to progesterone issues and I have all 3. During my last pregnancy, we were in a position to really seen that even suppositories weren't enough. At 7dpo my progesterone was around 24. By 16dpo, 2 days after I got a positive beta, my progesterone was tanking at around 10. I'm now on the PIO shots and these, finally, seem to be offering the support that I need. I'm currently 4 weeks pregnant and for the first time, my betas are doubling like they should be and my progesterone is nice and high and rising!
I'm glad you are seeing an RE. One thing I would tell you that I've learned from this journey is that if you feel that something isn't right, PUSH the issue. Most Drs are very very knowledgeable, but even the best of Drs miss things.
Feel free to hit me up if you have any questions!