AFP results

So last week I got the AFP blood test to determine risk of Down syndrome. The results came back as slightly elevated meaning that any woman my age has a chance of their baby having downs in 1:864. They said that my risk is 1:172. My doctor sees very positive and tried to convince me that the odds are still in my favor but I felt a wave of anxiety come over me. I'm scared to death. The doctor also said that this test is known to have false positives and therefore I was sent to get the harmony test in which I can find out for sure if the baby's has downs. I was wondering if anyone else has been through a similar experience? I am trying so hard to stay calm and be positive- but it's hard to not think the worst. I find myself getting mad and wondering why this is happening to me. I'm really struggling.  Any support is greatly appreciated. 🙁❤️