Reading Glow

I usually use OvuView or Fertility Friend so I'm trying out Glow since My Fitness Pal recommended it.

On the period days, it doesn't give any % of conception, but based on my ovulation I have an overlap if you consider the fact that sperm are viable for 5 days. How do you treat this? How accurate is the app?

Also how do you get the % to stay up long enough to see?

I had a miscarriage in April and almost bled out. It's been a slow recovery and I'm still about 70% in terms of strength and energy, so I really don't want to get pregnant right now, if at all ever again.