AFP positive lab work

My dr called to let me know that my triple screening came back abnormal and there is a chance of neural tube defects. I'm freaking out. I'm going to be getting an ultrasound and genetic counseling on Monday and possibly an amino to determine if there is a problem or not. I'm 19 weeks and have had 4 ultrasounds which all looked normal so we are very surprised. Has anyone had a false positive with this screening and/or can give me advise. We are hoping for a false positive so much.....We dealt with infertility for almost 6 years and this is devastating to us. Thank you in advance for any stories and reassurance.  😥