So let's see...that means you got your positive OPK on CD11, right? Well, I've never used the Dollar Tree OPKs before (although I have used their pregnancy test with no problem), but that might just have been your surge on CD11 then...which means you probably ovulated the following day on CD12. Ovulating on CD12 is not uncommon. I used to do that. Although on femara, I would usually ovulate a couple of days later, around CD14 or so. Best of luck this month!
I'm on day 13 today. I took the Femara October 14-18 which were days 5-9.
What cycle day are you today? And what cycle days did you take femara? As far as I know, femara does not cause a false positive...especially not two days after the last pill.