Ultrasound didn't show a fetal pole

Mrs.Hall
I went for an ultrasound last night, they said I was exactly 6 weeks. They didn't see a fetal pole or heartbeat. The doctor said if I have any bleeding or cramps I may be miscarrying. (I was completely not even expecting that!) I just assumed it was too soon. Next ultrasound is next week, I'm so worried. Any of you having something similar going on?