I'm still so scared and can't stop thinking about it

Hi I found out I was pregnant and went to hospital to confirm it and they did a ultrasound on me and said they couldn't see anything bcuz I may be early on but they never did the vaginal one! So everything was going good until my dr said my hcg level was at a 158 nod said that is super low based on my lmp which was Feb 8. I still think I'm way early on than what he say ! He basically said I may have a miscarriage so come back in two days to have it tested again! :(