Ovulation after IVF (Negative OPKs after IVF)

So we are in a holding pattern waiting to start a FET cycle after our freeze-all IVF cycle.  I have been testing for ovulation using OPKs (ovulation predictor kits) since cycle day 12 (CD 12-15 not shown below) so I can know when I ovulate so I can predict (give or take a day) when my period will arrive so we can start our FET cycle!

I normally get a positive OPK on CD 17.  Well, CD 17 came and went and the test line on my OPK was only 1/3 as dark as the control line.  I think it's interesting they tried to get dark on that day though.  Weird.  I googled: "negative opks after IVF".  Turns out, the internet is filled to the brim with ladies who turned an OPK positive 1 week later than they normally would.

I woke up this morning, CD 25, wondering if I'd ever ovulate this month, took an OPK, and it was ALMOST positive.  OPKs aren't hard to read (though most ladies on the internet at baffled by them).   With HPTs, if there is ANY sort of line it's positive.  On OPKs, the test line HAS TO BE AS DARK OR DARKER than the control line to be positive.  So finally, mid morning on CD 25 I got a positive! (See below.)  Overall, the OPKs went from light to dark to light to dark to positive.  Glad I stayed on top of them!

I estimate my period showing up anywhere from 10-14 days from today.  Which would make this cycle 35-39 days long!  Oy!

Negative OPKs after IVF cycle.
OPKs were over a week late turning positive after IVF cycle.