Lupus can do funny things to our bodies. It is totally possible that Lupus is the cause or even Hughes Syndrome (not sure if you have that). I have had numerous miscarriages and the fact that I had Lupus is what the docs basically chaulked it up to. All of my miscarriages were early, 9-14 weeks gestation.
One thought....since your doc says that that your progesterone is low ould be to talk to your doc about fertility pills/shoys that would help control the amounts in your system that is essential is maintaining a pregnancy. I did and I was initially pregnant with triplets. I lost one and had a set of twins that were early. Again.......just a thought.
I am sorry to hear about your losses, they are very traumatic each and every time. There are so many different emotions that rush thru you that I do not think I could mention them all. Do not blame yourself by no means. Talk to your doc about your different options.
Nancy