has anyone ever been through this? i am really struggling to keep my shit together.. last week i found out i was 4 weeks pregnant and had my first ultra sound

they told me it was too early to see baby my hcg levels were almost 5000. just 2 days ago, they drew my blood again, my levels were only 8000. i guess they are supposed to double? they did another ultrasound, still nothing but just a sac. i am juat really sad and confused. i am pregnant without a baby? i am not prepared to have a miscarriage. ive been doing research and you can still have a healthy pregnancy, the hcg levels we're just producing slow. has anyone ever been though this? ):