Is is normal to feel anxious about losing the baby.. even more if you already lost one. I think everybody heard about the story of the pregnant woman who died of brain hemorrhage, it has to be very rare hence why it made the news. Anyhow, you need to stop stressing for the sake of the baby and for yours :) are you being followed by a doctor for your pregnancy? you could tell him about your fears.. but also your anxiety.
Being hypochondriac while pregnant sucks, i know
try to relax and enjoy the little miracle growing inside you