5 week 2 day ultrasound

Hey girls, I just had my first ultrasound at 5 weeks 2 days and they only saw a gestational sac. She didn’t seem concerned because I’m still very early but I’m highly concerned because I’ve had two miscarriages in the past, last miscarriage I had low progesterone. With this pregnancy my progesterone was a 19.3 and HCG is doubling beautifully but my most recent labs my progesterone dropped to 13.6. Again my dr is not concerned because she said it’s still in normal range and progesterone fluctuates but I have been going crazy thinking about this. What’s the odds things will be okay?