So confused..ovulation with pic

Happy new year ladies! Baby dust to all in 2015! So...here is my dilemma. I have 5 fertility apps and 4/5 of them said 12/31 was my "O" day. Well hubby and I didn't have a chance to BD the days leading up to 12/31 and bc of parties we attended on 12/31..didn't get a chance to then either. Well yesterday 1/1 we did. For the hell of it, I took an opk yesterday afterwards and it was negative. Today 1/2 took one as well just to see and it almost appears like I'm going to be ovulating soon...the test line is darker today than yesterday. Please help me understand! Top pic is yesterday 1/1 bottom is today 1/2