Glow is messing up my cycle

My period was supposed to come the 17th it came the 26th not only did I waste money on pregnancy tests. I thought I was pregnant and had missed my period then 9 days later it shows up now Glow is saying I am most fertile the day after tomorrow. my period ends tomorrow but the day after I have 22% chance. on my Glow calendar for next month I only have 2 fertile days does that make any sense to anyone ?