Low and slow HCG

I'm about to experience my third MC in about 5 years (I have 2 children). My HCG draws have gone as follows: 10DPO - 12 12DPO - 19 16DPO - 54 18DPO - 86

has anyone had low and slow rising HCG like that and when did your body finally realize it and start bleeding? I have had no bleeding yet, just 2 days of light brown spotting. Just want it to be over so I can start again and my doctor doesn't seem to be much help in offering a timeline!