LG - I don't know anything about Clomid sorry. It is something to think about though.

If it was me, i'd just keep testing with OPKs for a few more days until you get a cover line from FF. If you don't get a cover line, then maybe its time to see the dr. But i don't really know about these things, because since using OPKs i've got a +ve, even if its late like CD24.

I'm sorry i haven't been much more of a help.