Someone help! What's going on?

C.
I am on cycle day 37. Earlier this cycle, I used a clear blue digital OPK and got peak fertility on 12/8 (CD 12). I haven't got my period yet and as of this morning, I've gotten negative HPTs. 
I was at my friend's house for dinner and noticed some slight pain on my right side/ovary area which made me think, "maybe I should use an OPK?" So I came home and got peak fertility again! What is happening? We BD'd just in case but I'm confused. 
Edit: please respond if you're viewing! Even if it's just for encouragement-- I feel like I've been through a lot of ups and down with TTC lately and could use some positive vibes!