Hi M.!
With my first child, I was sick the first trimester, like normal, then it tapered off.
With my second child, I hardly felt sick.....until the last month I was sick ALL the time to the point of vommiting and needing IV's.
My point is, I think every women and baby are different. Try not to worry yourself sick about it. Just listen to your body, and you will "know" if you are healthy or not inside.
I will pray for you today. I'm sorry for your fear of a miscarriage, that would be emotionally hard to get over in your case.
:o) N.