Tiny sac 2-3 mm

At my first ultrasound last week at 5+6 doctor saw only a tiny sac measuring 2-3mm, no yolk sack or fetal pole. Said I’m measuring about 2 weeks back 😟 He was not very optimistic, going back for a new check next week. I’ve had 3 early miscarriages before and we’re trying for our first baby. Im worried sick. Anyone out there with a similar experience? How did it go?