Hello i recently found out im pregnant i have my first doc appointment August 5th but I've been seeing a carenet nurse she did a regular urine test it came out positive and due to my last period she estimated i was 8 weeks i went in yesterday and i only had a 17mm sac no baby no yolk she determined i was 5/6 weeks pregnant. She just did an ultrasound she did not perform a vaginalscan. Should i be worried about a miscarriage? Is this something that can usually happen without any risk?