6 week Miscarriage

I believe I am going through a miscarriage and just looking for experience of what to expect. I should be 6 weeks 5 days based on when I ovulated, but went to ER yesterday and was measuring 5 weeks 6 days. There was a fetal pole and heart beat at 77bmp. No yolk sac visible though? Not sure how that even works though. Hcg was only 2713. They said threatened miscarriage. I’m honestly not holding out hope. I know this is going to happen based on horrible cramps and bad low back pain. I’ve been passing tiny clots last couple of days with lots of red spotting. This morning I did have a gush of blood and bigger quarter size clots. My question is, what should I expect as far as bleeding and what I’m passing when Gestational sac is only 6 weeks 0 days now. Is it just going to appear like a bad period? Or should I expect a bigger passing of a substance? I can’t believe I’m going through this. Please tell me your experience so I know what to expect! Thank you. I do have another ultrasound on Tuesday so maybe I will know if it’s been completed by then…