Implantation issues

Hi ladies, I'm wondering if anyone can point me in the right direction. I've been ttc for the last three years, had two mcs, one in Oct 2016 and the other June 2017. Still no baby. In the last year, I've had three chemical pregnancies. Testing clear positive for three or so days then AF comes a few days late and tests to back to BFN. I've been using bbt and opks the whole time, I have 28 day cycle and all tests so far ( semen analysis, day 21bloods, full blood panel, AMH ) have all come back normal. I feel there is a reason I'm not implanting properly but feel no one is taking it seriously. I'm on the waiting list for IVF and I'm getting a HSG done on Nov 11th. Is there anything else you can think that I should request treatment wise? I feel that IVF will fail if we don't get to the source of the issue! Any help much appreciated x