Hidden twin?

Hey Ladies! Have any of you all ever experienced a “hidden twin”, or have received an ultrasound. informing 1 baby around 7 weeks then a few weeks later find out that there’s 2?!

Does this ultrasound show you all that it should?

My obgyn is referring me to MFM clinic at 8 weeks to have another scan done to confirm a twin pregnancy. My blood work Hcg levels have been high, also my symptoms of pregnancy are extreme.

This is my 10th pregnancy, (never had twins before) so all of this is new to me this time around. I was informed from the MFM clinic twins might -> MIGHT , not be seen until about the 10th week of pregnancy.

Opinions please!