I bought a bunch of OPK's for this cycle, and did 5 all around my expected O day and got neg, neg, neg, neg, neg!

I can't possibly test at work at the suggested 2pm, so the only time I can test is at about 7:30 when I get home - maybe this has something to do with it? Or possibly I just didn't O (again) this month. I didn't seem to have any EWCM, and I will have to wait till tomorrow for my temps to reveal anything.

As a side note, does anyone else have a problem with no/very little EWCM?
And has anyone used pre-seed to try to help?