Seven weeks pregnant, recently started bleeding, dark red. Sorry for t…

Seven weeks pregnant, recently started bleeding, dark red. Sorry for the details. My lower back hurts a little. I took 2 tablets of Dufastone as my doctor advised. Since the first days I knew I was pregnant, I've been taking it twice a day. I'm very worried. The pregnancy is long-awaited. Can you tell me what you do in such cases? What symptoms occur with miscarriage and threatened abortion?