Er trip/ normal fetal heart rate at 5 weeks

Just left the ER for cramping and brown spotting all day that turned red when I got home from work. Spent 5 hours at the Er and had an ultrasound done. They told me that the fetal heart rate at 5 weeks is too low at 92. Everything I read online says its normal. Have any of you had your us done and gotten what you babys fetal heart rate was?