When we were TTC'ing (I have PCOS), I had a u/s on CD45 - and my lining was thin (5.4 mm). I went to a chiropractor - who discerned that there was an issue with two of my lumbar vertabrae (L3 & L4, I think). They were compressed and blocking energy and blood flow to my uterus - but improved after a few adjustments.
About six weeks later I started Clomid cycles with my RE. He was initially hesitant to try Clomid due to my lining issues, but went ahead with it b/c we didn't have the insurance coverage for injectibles. I did three cycles, got prego on the third - and my lining was perfect every time. Here are my stats:
CD45, unmedicated cycle: 5.4 mm
CD16, Clomid cycle #1: 9.2 mm
CD16, Clomid cycle #2: 8 mm
CD 16, Clomid cycle #3: 8.4 mm - got BFP!
In my case, I really think the chiropractic treatments helped (plus, I was able to get them covered by insurance).
My RE did also mention Viagra as a potential treatment for thin lining issues b/c it helps increase blood flow to the uterus.
Good luck and sorry about your recent m/c ((((HUGS)))).