twinges in ovaries but neg opk

[StranjeGirl]

I'm so confused right now. Im on cd 12 and last month I o'd on cd 13. I have been using wondfo internet cheapies 3-4 times a day to check for a pos opk. Today I got what seemed very very close. Maybe slightly lighter than control line when wet, but dried as dark as. I assumed that my next test, which was about 4 hours later, would be a clear positive. Instead it was a faint line. However, right now I am feeling twinges in my left ovary like I am ovulating. Any thoughts? Anyone ever had an almost positive turn negative before? I usually get 2 days of surge. Or anyone get twinges a day or two before O? Thanks!