Opk help please

Wish I'd asked for a second opinion! On 15th I had what I though was an almost positive opk and was certain it would be positive on 16th as it was that dark but it went really light again and today it's barely there, but on 16th I had left pelvic pain (which is what I get when I ovulate) on glow and ovia I was in the start of my fertile window on 15th. Also had ewcm at that time and today it's gone sticky. I didn't record a positive opk as I wasn't 100%. 
Does anyone think I should mark it as a positive on 15th?