Pregnant within one month of Miscarriage

I'm seeing posts about women who are nervous or shocked about seeing a positive test a month after their miscarriage. It is very possible to happen! here is my story.

In December I had my first ever positive pregnancy test, December 12th. I would have been 5 week since I waited a week After my missed period. I tested postive and the next day had my blood drawn! it was only 50HCG it was low, but not quite a good indicator yet of a failing pregnancy. well 4 days later I went to get blood work again and my hcg didn't even double it was only 93. They had let me know to prepare for a miscarriage as this was not looking good. I had been spotting brown for 2 days but they told me that could have been old blood. December 17th,2017 the heavy bleed began for about a week.

Fast forward to January 17,2018, something just didn't feel right. my period had not started which I had been cramping so I was surprised. so I said what the heck I'll take a test and see what it sees. I took it at night and it was the darkest pregnancy line I had ever seen. I took 2 more that night. And all three were very postive. I was shocked. I called my doctor and asked her what I should do. So of course they wanted me to get a blood draw because it is not common to get pregnant right after a miscarriage especially because I had no period between. My hcg levels were 859! Four days later they were almost 5,000 fast forward a few days later I had went to my first ultrasound to see the fetal pole and the baby was measuring right to the date. 2 weeks later I went in for another ultrasound to find the baby had grown even more. Fast forward to today, I am now in my third trimester of pregnancy and baby girl is due in September.