Frustrated 😢

Okay so I found out I was pregnant on Friday , according to the calculations I’m 4weeks 5days I came to the emergency room because I felt pain near my kidney so I was thinking I had a uti , they did an ultrasound and they said they don’t see the baby because I’m too early on. has anybody ever had this issue ? Because now I’m worried they said my hcg levels are in the 900 because it early and this is driving me crazy because I’m so worried