Stressed out!

Heather
So today, I went for my first appointment (I'm supposedly 5weeks 2 days) and they did an ultrasound. Why they would do one this early blows my mind because the tech kept telling me she didn't see anything and would have the doctor go over all of it with me. And so I begin to freak out because there should have atleast been a gestational sac right? Well the doctor comes in and let's me know I have a gestational sac that puts me at about 5 weeks, but that's all he can see. So now I'm doing blood tests 48 hrs apart and they said they would call me on Monday. I didn't get a congratulations or anything. I feel like there is a dark cloud hanging over this pregnancy now. Has this happened to anyone else?