Low heart rate at 6 weeks??

Went in for an ultrasound and she found a heartbeat but mentioned it was “a little slow” and it “must have just started beating”.. i never even thought to ask what the heart rate was. She said she wanted to schedule me in 2 weeks for another growth scan. Now i am putting together all the pieces and reading all sorts or articles about the high chances of miscarriage when your baby has a slow heart beat. I’m freaking out and mad at myself that i didn’t ask what it was. I just figured if she didn’t flat out say she was concerned, everything was fine. Now i have a feeling why she scheduled me for that growth scan? Anyone have any experience with this, good or bad i want to hear!