OPK. Two tests, different results... Help!

Okay, this is my second month really TTC. I didn't use an OPK last month so I wasn't exactly sure when I would ovulate. This is my third month of BC after being on for around 8 years. My periods since going off BC have been pretty regular, 28-29 day cycles... Periods last 3 days. 
I use two different tracking apps and both said this was my fertile period and predicted that I would ovulate yesterday. (My period was June 4th). I have been using ClearBlue Digital this month and have gotten the flashing smiley face since Tuesday morning. This morning I used the CB Digital and Walgreens Ovulation Strips. The CB test was still flashing smiley, but the Walgreens test said positive LH surge. 
I don't know which one to trust! Anyone have similar experiences?