Cycle question

Hey ladies. Have a cycle question for ya. I used Glow last month and thought I totally nailed getting preggo (1st time trying) and was simultaneously using an app I've been using consistently for over a year at the same time. I spot for a day or two prior to getting an actual flow. I notice Glow tracked this as period day 1 this month and the other tracked the actual flow as day 1. Glow has me at a 31 day cycle and the other app says 28 day. Do any of you also spot regularly before a flow?  If so, do you count the spotting as day 1 OR the day you start the flow as day 1?  This is making it hard to determine ovulation. Thanks!