Help! Need opinions


So , according to the app I am 4 w 3 d pregnant. But I’ve had a miscarriage last month , can’t remember the exact date. So I went to the hospital today just for some mild cramping so they gave me an ultrasound and took blood work. They said they can’t see anything yet but that I have a thick lining which is supposed to be good ? And the doctor said my levels are a little low , they’re at a 398 right now. But I’ve read a chart that says at week 4 levels from 5-426 were fine. Now I’m worrying 😩 has anyone been in a situation similar and turned out fine ? What were your levels at 4 w ?