TRIGGER WRNING.... possible miscarriage

I’m about 5w3d and have been having some bleeding since Thursday. I went to the ER today and they performed a transvaginal ultrasound to which they said there was no intrauterine pregnancy identified. I was told to come back in 2 days to see if my hcg levels have increased otherwise they’re considering it a threatened miscarriage. Has this ever happened to anybody be who went on to have a healthy pregnancy?