Hi, I Am 8 Weeks And 3 Days When I

Hi, I am 8 weeks and 3 days when I went to my doctor for first u/s that was January 4. Because I noticed a brown spotting, Dr. do ultrasound she said I'm only 4 weeks and 3 days pregnant the baby is so small in measured but there a heartbeat with 119 bmp. I was confused..I calculated base on my LMP..she told me to come back next day for another ultrasound and she advised me too take duphaston and duvadillan, went again January 6. She said the babay is now growing and this time no heartbeat.. This things going me paranoid so devastated.. I'm still praying and hope..some advice will appreciate.. Thank u