AFP Tetra results

I received my results back from the AFP Tetra test on Saturday and it stated that the test came back positive.. 😣 at the bottom it states that I am at risk for my baby being born with Down Syndrome. I am 16 weeks pregnant with my second child and I am curious if anyone else has experienced this and am looking for some feedback. I also had the NIPT test done as well at 12 weeks and everything was low risk! So I’m confused at what happened between then and now. Someone please give me some feedback ...I am petrified! 🙏🏼