Retroplacental collection with low lying

At 12 week I got bleeding and was admitted to hospital. Was kept under observation and bleeding was stopped through injection. Scan showed low lying placenta with 10 CCS retroplacental collection but after 3 days in hospital I went home on bed rest. After a week started getting brown bleeding which is going on since 8 days. Again a scan was done with fetal movement n 156 heart beat but retroplacental collection reduced to 6.8 CCS n placenta still low. I'm on susten300 n duphaston.kindky advice if this will get rectify and how n I will have happy delivery. My first child was born with normal delivery , six year back with no complications n I never had any miscarriage. I'm on thyronorm 87.5mg. Tsh 4.8 now went to 100 mg