Kinda freaking out now!

So I saw my Dr a week ago and it's been eating at me ever since! I went to a boutique kind of place for a gender ultrasound at 16 weeks and I was told I was having a girl there was no doubt in their minds but I went to my dr a week ago (19 weeks)  and when I told her this she made a huge ordeal saying it was WAYY too early to tell and that she would never believe what a tech said...now I'm super nervous! I felt like 16 weeks was totally safe? Do you think the dr is being dramatic or should I have not told anyone I was having a girl?? I've always worked at hospitals and our techs always know what they're doing and just bc they aren't the dr they aren't stupid so I assumed all was ok?