7th embryo transfer. Always get spotting 3 or 4 days after transf

Hi
I have been doing Ivf for two years now and coming up to embryo transfer number 7.
Unfortunately none have worked so far.
My first transfer ended in a blighted ovum d&c.

I also had a hysroscopy and d&c before my last transfer.
Everything looked fine according to the dr there is no medical reason why they shouldn't be working.
The my first 3 embryo transfers were from non medicated cycles but I have high hormone levels so opk always come up positive so I had to go to medicated cycles to control things a bit more, I've had 3 medicated cycles
Each medicated cycle I've had I start spotting 3/4 days after the transfer which then continues till after my 2ww when I stop meds and get my period.
He dr said it may be due to the drugs but I start them a week before the transfer and nothing happeneds.
I have no idea where to go from here, I've been doing fertility treatment since 2010 now, I was lucky enough to have my son in 2012 after 8 iui's.
Mentally I'm ready to give up but I have to keep pushing for the possibility of having another child.
I have no answers, I don't know what to do from here. Has anyone had lots of unexplained negative results, has anyone had this spotting a few days after transfer?
If anyone has been or is in a similar situation and can shed some light that would be fantastic.