Go by glow or my last two periods?

Tara
Hi all,
​My last two periods were 25 day cycles. Glow says for this month I'll start on day 29 which would be Saturday. So should I go by glow or my last two periods? I am due tomorrow to start AF if going by my body and I have not one sign of AF other than light cramping, sore breasts, and back pain. I always spot brown days before and I have had nothing. I caved and have taken a few tests and I thought I saw a faint yesterday but nothing on the test today. Am I still too early to test? I am confused. 
​Background on me, I have one healthy two year old and yet this year I have had a mmc and a chemical in a sixth month time span. Been a rough time to say the least. Drs say "bad luck" all testing came back fine. 
​Just looking for guidance and some insight.  
​Thanks-