Weird ultrasound

Colleen • Pregnant with our first! It's a girl🎀
So I had my first ultrasound yesterday it was vaginal since it's so early they doctor said they could only see a small sack with liquid in it and they also said I have a odd shaped uterus
I took 3 pregnancy test on the 15th of this month all positive 
I'm so worried that it's not a baby 
The doctor said he couldn't tell me if I'm pregnant or not
Help!?!