Spotting and Cramping (1st Trimester)

I am not sure how far along I am, I just know my last period was Feb 12. I had a positive test March 21st and this morning woke up to bad cramps and light bleeding. I went to the hospital and both blood and urine tests showed positive for pregnancy. My hormone levels are a little high. I had an ultra sound done and a vaginal ultra sound too but they said baby is too small to see (2.4cm) ? Now I am told I am running risk for miscarriage due to the bleeding but they are not sure exactly what is causing it.

This is my second pregnancy, had no issues with my first baby so this is the first time I'm experiencing something like this. I am worried because I do not want to have a miscarriage 💔. Me and my boyfriend are so happy with the need of another baby coming to the family. I was asked to stay in bed rest, no intercourse and keep any activities to a minimum.

Ladies please help me out with this, what could this be? I will be following up with my OB Monday morning but any advice or help that can ease me thru the weekend will help!!! 😭