Help!

I went for a gender scan last week, at 16.2 weeks the baby was lying awkwardly and it was hard to find the gender. At first I was told a girl.. Then he said its a boy , then he told me to come back in 2 weeks to confirm it is a boy because he wasn't that sure. In my eyes that's a willy 🙈 I'm happy either way but I'm just wondering if this has happened to anyone and they have went back to be told a different gender! I just want to buy baby things already 😍😍😍