How fast will hcg go down after mc

I am 4w2d pregnant and started bleeding pretty heavy today but my tests are still darker than before. I have really low hcg, my blood test Saturday was 6. I went to my ob and he said my cervix is closed which is my only glimmer of hope. He did another blood draw that I receive results tomorrow and another set on Thursday. Here are my tests over the last few days and the bottom 2 are from today morning and evening. I will continue to test at home bc I feel like with hcg as low as mine they will go negative pretty quickly if this is a miscarriage. He said I have a 50/50