Help please!!

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I just had my first ultrasound, I'm 6w6d according to my LMP. The doctor could only see gestational sac and yolk sac but no fetal pole. She said its a 50/50 chance that things will go well. She scheduled another u/s next week. I was so depressed that I scheduled another appointment with my old doctor today and she said according to my u/s it looks like im only 5 weeks maybe 5 1/2 weeks and its too early to see the fetus. Has anyone experience this? Im so scared, this is my first pregnancy.