Help! When did I ovulate?

j
I appear to have ovulated earlier than normal this month, but can't determine when! I'm getting three different predictions from each app. Glow says CD 16, Ovia says CD 15, FF says CD 14. I got a peak OPK on a Clearblue Digital Advanced on CD 15. How could I have ovulated before then?  
My cycles are an average of 33 days, so this looks like it will be a much shorter cycle than average. Not sure what has caused that, either.  Temps seem to be lower post-o, as well.  I appreciate any insight you all may have! Thank you! 
This month's chart:
Previous months: