Should I be worried?

Karina

Apparently i caught my pregnancy very early. I went in last week on Monday and all they saw was a sac measuring 5 weeks I should’ve been about 6/7 weeks. Now I went to the er with severe nausea and vomiting they did an ultrasound and the found a fetal pole measuring 5 weeks and 5 days. But how if my sac was measuring 5 weeks exactly one week ago and they didn’t find a heartbeat. Not to mention I had light cramping last night and no blood but I woke up today zero symptoms. Like no nausea like every other morning. I’m super scared now. Could I be having a miscarriage? Or is this step by step development normal???