Hcg at 6 at 4weeks, when will I finally miscarry?

My appt isn’t until Friday with my OB but the other night I went to the hospital because I was nervous because I’ve been having spotting and had a miscarriage 6 months ago. The nurse told me to expect a miscarriage because 6 was very low for being 4 weeks pregnant and since I’m spotting. I’m just wondering if any of you experienced this or how long you think it will be til I miscarry? I figured since my hcg was only a 6 that maybe I would miscarry faster with it being barely there. I’m just not sure.