I usually ovulate between CD 16 and CD 20-something, so this isn't really abnormal for me. Had been running earlier (closer to CD 16), but I really started getting back into exercising - like at least 30 minutes of treadmill more days that not, and have just lifted the minute requirement to make sure I cover at least 1.5 miles before my 4 minute cool down... so I think maybe that's got something to do with it. Been checking every 6 hours and my last OPK (5 PM today) is the first real contender for CD 7 (the negative but freakishly dark one I got early this cycle). FX the one I'm checking in 10 minutes is even more promising!