You know, I think something immune must be going on that you had four normals and four CPs. I am so sorry for all that you have been through. I had one CP and it was very physically and emotionally difficult.
Personally, I would keep cycling and looking for normals. At the same time, leave no stone unturned with immune stuff. Check out this blog: http://lifeandloveinthepetridish.blogspot.com/
This woman had seven miscarriages (some were normal embryos) and is finally pregnant and past 20 weeks. Her story is amazing.
Wishing you the best!