Help.... no gestational sac seen at 5 week ultrasound scan

I am 5 weeks 1 day pregnant (1st pregnancy) today morning as I woke up I had brownish discharge( not much in amount) with intermittent cramps. Immediately referred to hospital. Doc asked for ultrasound scan as without scan she can’t help me enough. But after ultrasound sonologist said that she can’t see any gestational sac as it’s an early scan, as I may have ovulated late. She asked to repeat scan after 2weeks. I had that brownish discharge whole day on and off but too little in amount. Any one who has been through this plz help... Is this brownish discharge a threat to my pregnancy.. is it a sign of miscarriage???