Fetal heartrate

What is the normal fetal heart rate at 34 weeks? My baby’s heart rate is normally in the 140’s - 150’s but at my 34 week appointment it was 123bpm the midwife didnt say anything and said I’ve got a very happy baby but thinking about it now I’m like, I wonder why it’s now low compared to what it usually was?, maybe I’m just over panicking at everything now 😄