Hi OP, so sorry for what you're going through. I had an early loss in August last year too and it's awful. You're in the middle of it right now and I completely understand the need to plan ahead! I never had a cause identified for my loss (interested that you got results for HCG and Progesterone, how did that come about?) but I also have PCOS and had irregular cycles. If it helps, I can tell you what I did after my experience and how it's gone...
First just be aware that it could take your cycle a while to resume. For me it didn't return until October, after my loss in August. This is your breathing time really, even though it is very hard waiting to start bleeding again. When I was ready I read a book called "It Starts With The Egg". It details all the latest research into what might optimise your eggs for pregnancy - there may be a section in there about optimising progesterone but I can't remember. I found the section dedicated to Pcos really helpful and I followed most of the advice supplied - I cannot possibly say whether I wouldn't have got pregnant again without the regimen, but I did, and reading it at least made me feel like I wasn't completely powerless to help my situation (it involved a lot of supplements, which is a personal thing as to what you feel comfortable taking) and some diet changes. I had already taken myo-inositol for a long time prior to pregnancy and really found it helped regulate my cycle in PCOS, if you haven't ever tried that. I got pregnant again, in November, on my second resumed cycle after miscarriage - I am now almost 35 weeks along and all thankfully seems really well.
A word on progesterone - I was prescribed it because when I started bleeding in August I told them (truthfully) that I had had a suspected miscarriage a couple of years previously, and at the time I was seen for the bleeding at the EPAU my pregnancy still looked viable on ultrasound. I didn't have time to start taking it because I lost my pregnancy later the same day. I kept it under my bed for future use but never needed it in my second - part of the reason I didn't just take it anyway is that ironically it can CAUSE bleeding, and I knew that bleeding would tip my sanity over the edge - I dreamed I was bleeding constantly in the early weeks of this pregnancy.
Sorry for the long essay but my heart goes out to you so much, especially if you aren't even through the bleeding stage of your loss. It is awful, truly, and don't let anyone or yourself tell you it didn't matter because it was so early - take your time and don't rush resuming trying until you're ready emotionally (whatever that looks like, I'm still not sure!) as well as physically. Huge hugs