Scared to death

Tessy • I am 31 and ttc for about 3 months with bf of 7 years and 2 months. We both already have children from previous relationships. I have 2 boys and he has 2 girls but we want a child of our own.
As of 2 days ago I had a single cramp I went to the bathroom and wiped blood immediately went to the ER and the did a hcg hormone count and it was at 400....went back to the hospital yesterday because I felt blood come out but it was older a normal period they do another count and another pelvic exam my cervix is still closed but my count dropped from 400 to 200 within 24 hours and they tell me I am more than likely gonna miscarry...that doesn't make sense to me tho because I have no pain just bleeding and it's not heavy bleeding just like a period,a closed cervix, and I haven't passed any kind of clots or tissue at all...I'm confused.