Guidance please!

I’m not sure when I truly ovulated. According to the app it was the 13-18. We bd on the 13th and 17th. I could have sworn that I had meschelsmertz (sp) pain on the 17th. I thought I would be okay to start testing and used the frer since the app says my cycle will start on Sunday, but got a bfn. I’ve taken a clearblue and got what I believed to be a faint positive. How many dpo do you think I might be and if I’m getting negatives do you think I’m out?

Sorry for the long message.