Trying not to stress

Brittany
According to the first day of my last period. I should be 6 weeks today, but I ovulated late. I went in for my first appointment. They drew blood and I had an ultrasound, but she didn't use a vaginal ultrasound. Just a normal abdominal ultrasound. Anyways. She couldn't see much and after a minute or two she see what she said looked like a flicker or the start of a heart beat. Why would they give me an ultrasound so early and not even use a vaginal ultrasound?! I'm worried sick now. The tech didn't tell me much at all and wouldn't answer many of my questions. After the ultra sound they just walked me out and gave me another appointment for next week. No one answered any of myquestions or anything. I need some advise and reassurance.