Ovulating??

Help! First time TTC over here! Today is cycle day 16 of my 28 day cycle. Last night I got a pretty strong opk test line. Just tested again this morning and the line is more faint. I think my LH levels are higher at night than in the morning just based off the past few days of tests, but any insight would be helpful. Most apps had me ovulating yesterday?? Was my line yesterday in fact a positive opk? Might I add that Glow is the only app that has me ovulating on Saturday, December 8th.