NIPT wrong gender?

NIPT said boy. A few days ago (I'm 18 weeks) went to the ER for bleeding and cramping. I thought it was all over, it was so scary. I'm on bed rest and I see my doctor on Monday. At the ER the lady doing the sonogram said it looked like a girl. She showed me the three lines. She said she was 99 percent sure it was girl. I was so scared that I just wanted to know the heart was beating. The next day I had another sonogram and the tech said she guessed it was a girl. At the time I didn't care. So while I'm resting I'm trying not to worry, but my head is going wild trying to figure out why they would find a y and if it means something dreadful like a genetic disorder. This is my first pregnancy. I don't have any pictures. I hope that my doctor can tell me what's going on!!!