So Confused!

Has anyone ever bled like a regular period just to find out 4 days later that you were pregnant, had to be put on progesterone tablets and went on to have a healthy pregnancy? I was due for my period September 18th I started bleeding on September 15th on and off for a couple of days and then had light brown spotting all the way up until September 22nd. I felt this was unusual so I decided to take a pregnancy test and got a Positive right away. I am still seeing the brown discharge when I wipe I went to the ER to have my HCG check on the 22nd at it was at a 66 my ovulation day was on September 4th. I had a miscarriage back in June on my birthday😞I’m so nervous and confused right now.