Nipt test vs ultrasounds

So at 11 weeks I had nipt testing done and I got girl gender result, I had a scan at 15 weeks and was told boy but I thought it could be wrong since it was still early. Well today at my 20 week scan boy again. I’m so confused my dr said that nipt is accurate. Has this happened to anyone. I was hoping for my little girl 😩 how is this possible I thought blood test was more reliable than scans