Someone check my math?!

A. ❤️
Does this make sense to anyone or do I have some numbers off? 
8/5 was last AF
Small brown spot on 8/16 (??)
8/25 was O day according to glow
AF was due 9/8
BFN 9/4 and 9/12
Implantation can occur something like 6-12 days after O which would at the far end be 9/6
HCG doubles ever 48-36 hours. Again going with the far end I get:
1 at 9/6
2 at 9/9
4 at 9/12
8 at 9/15
16 at 9/18
32 at 9/21
FRER can detect HCG at 25 so that means I wouldn't hey a BFP till after the 18th?!
I'm a full week late now and too hopeful. No PMS or anything. Very light cramps here and there. Lots of CM since O. 

Glow Resources

Let’s Glow

Glow is here for you on your path to pregnancy

Glow helps you navigate your fertility journey with smart tools, personalized insights, and guidance from medical experts who understand what matters most.

25+ million

Users

4.8 stars

200k+ app ratings

20+

Medical advisors