Resting Heart Rate Fell, Cause for Concern

Okay ladies you can tell me if I am just being too anxious. For some history on why I am anxious I had a stillbirth last year and I really want this baby to be okay.

I am 6w+4. My resting heart rate for the last few weeks has averaged about 72. Today I notice my resting heart rate is down to about 64 which is near my pre pregnancy heart rate. Do you think this is a bad sign or am I just stressing to stress?

I am so nervous and my first ultrasound isn’t until 9w.