"Miscarriages - I was always told "it's nature's way" and to just accept it."
Right, I'm familiar with that statement. A standard line, no doubt, that's suppose to offer comfort somehow.
Although you don't own animals you have something going on, obviously. You've explained plenty of parasitic symptoms; therefore, this would be a consideration to look into as a concern. Naturally, a microscopic examination would make sense to try to figure out what's going on. Next step, clean up the body. Heal. Try again.
Since parasites and fungi aren't a possible consideration within the medical establishment, many women will continue to suffer.