Ovulation prediction question...

Back in April (14-17th) I had spotting, nothing like a normal period, so I didn't mark on glow that I started... Just got negative results back from a blood test, so I changed it and said I did have a period those days cause I figure I must have... And glow is now saying I only ovulated April 18th (22%) and April 19th (8%)... Anyone have any idea why? I thought you were fertile for about a week... Any advice is welcome please!