6 weeks 3 days bleeding

So last Wednesday I went for a ultrasound .... only see the sac.... today at work I began bleeding heavily so I went immediately to the er .... they gave me a ultrasound... saw the sac yolk sac and heartbeat of 112!!! They said I had a subchorionic hemorrhage.... but also said couldn’t rule out miscarriage .... has anyone had this happen? I have a scheduled ultrasound Friday I’m super nervous. I have had 3 miscarriages prior to this but my hcg has never went past 100 it is at 19,228 right now