Feeling down

So I used opk for the first time this month and I tested 2 times a day from 2 days after my period (morning and night) and I never got a positive so I don't even know when (or if) I ovulated. Darkest test I had was on 10/11 in the morning but was told it wasn't positive (pic below). My periods usually always show up the 28/29th of each month so now I'm just watching and waiting and hoping that I got pregnant this month even though I don't know when I ovulated.. Any pointers for next month? Is bbt more accurate?