Hi @bfnancy, thank you and I'm also sorry to hear about your loss. It's never easy to cope with it.
Regarding the rhr, I noticed a big 3bpm jump on 8 days after my peak on opk (Saturday 7 August 2021).
Then it remained the same for 11 days.
On 14 days after getting peak it remained same so I tested and showed bfp making me 3+4.
However, last week Wednesday 18 August 2021 19 days after peak, my rhr dropped by 1bpm and thought something terrible is happening. Everyday it dropped (4 days) until Sunday 22 August 2021 it jumped to 1bpm.
Monday 23 August 2021 morning started to bleed with rhr increasing by 2-3bpm increase.
Tuesday 24 August 2021, pregnancy test and showed by, as not pregnant on both clearblue fertility monitor and clearblue digital with weeks. However, got an extremely faint line on first response early and first response rapid with the HCG blood test confirmed it being extremely low for 5+1.
Only yesterday (Wednesday 25 August 2021), rhr dropped my 1bpm and same again today dropped by 1bpm.
I'm sorry if I can't be much help right now. However, I would say to remove the Fitbit and try to relax/divert your mind elsewhere (easier said then done I know). Lots of hugs.