Hi M.,
I can tell you from experience that there are few things more difficult to go through than a miscarriage. I actually went through 4 of them before finally having my son. He is a little miricle to us and we also hope to have at least one more.
The heart beat can be very difficult to find before 8- 10 weeks in some women's bodies. I don't know why- but this is what I have learned from being in many doctor offices. So I would have at least once more ultrasound/dopplar closer to 10 weeks.
One of my girlfriends had something similar happen. She had thyroid issues too. The pregnancy tests barely showed enough hormone to indicate she was pregnant, and the dopplar was weak as well, till she was further along.
She had many fertility issues for the first part of her marriage (doc said they were thyroid related) and then they finally were able to have one. Now she has 3 kids...lol
Try to relax if you can- as divine providence knows what is really happening inside you. There is an answer already as to whether your baby is strong enough to go the distance. And whichever way things turn out- I really believe we are not given more than we can handle- including loss.
My personal faith was shaken a few times in losing 4 babies- but now, on the other side of it all, I can see in part the things I learned through those circumstances that were necessary.
I learned to accept my own lack of control and that there is grace in all things, pain included. I really do know the fear and desperate feelings you are experiencing, and all I can tell you for sure, is that God's timing is perfect. I got tired of hearing this, but it was the inescapable truth.
My son came when I was about to go back on the pill and had no intention of getting pregnant. I also had just come to a place in my life where I could forgive my father for abuses suffered and within 2/3 weeks of this I got pregnant with my son. I was distraught thinking - oh no here we go again, but there was healing in my forgiving my dad, because my son is here today with me.
I do not believe this is coincidence and so it was another powerful thing I took from all my other losses. I think sometimes, our bodies suffer from emotional/mental stresses and trauma to the point we shut it's ability to function down- including reproduction.
Having said all that, I will just gently tell you to try to stay as relaxed as possible, get another test in a few weeks and in the meantime know your baby will do what is best for you and themeselves. Grace makes sure that all are taken care of, even if we don't understand the way this plays out.
I see the grace that covered me during those losses and the grace that covered my last pregnancy and brought it to term. You will come through this, and be more (not less) either way it goes.
Praying for you-
D. :)