Possible miscarriage?

Amber

I recently found out I was pregnant 5/14/18, my last period was 4/07/18, the doctors estimated i was about 5-6 weeks then. I just left my first transvaginal ultrasound 6/6/18, and the doctor can only see a yolk sac, and estimated I was 4-5 weeks. It’s either a possible miscarriage or I’m a lot earlier than I am. I also am not sure what the two antenna things sticking out of the yolk sac are.