I have no clue what's going on

According to Glow I'm 7 weeks today. My lmp was 7/5. My fiancé and I had sex on the 18th..glow said I wasn't ovulating till the 22nd, so I didn't think there was much of a chance of conception.

Anyways, today I've had cramping all day and light pink spotting so I went to the ER. I had a SCH in my first pregnancy so any type of bleeding makes me worry.

First they said my hcg levels were low, 580 I think. And they kept questioning how far along I really am. The doctor mentioned the chances of ectopic pregnancy or miscarriage.

They did a transvaginal ultrasound and the woman said she didn't see anything at all but I was eventually told that there is a sac, where it should be, but that's really all they can tell me for now. I need to have my levels checked again in a day or two.

I just don't know what to think and I'm so worried.