Disappointed in my GLOW fertile prediction.

So I downloaded another app. It has me ovulating 17 days into my cycle. Glow has me ovulating 14 days in. This time I got smart and bought ovulation tests. Tomorrow is my peak ovulation day according to Glow. The ovulation test is very faint. I'm disappointed I been having sex every other day during the fertile window glow has given me. And all this time I should have been having more sex at a different time. I have irregular periods, off by a couple days. But here glow has be ovulating to a 28 day cycle when my cycle is more close to 31 days. No wonder why I haven't gotten pregnant.