I have PCOS, so my cycles are all over the place. My last cycle was seven weeks. This one I appear to have ovulated at 2-3 weeks after my period, but in all the time I've been TTC, I've never got a positive OPT! I have had a chemical pregnancy, and am currently pregnant (waiting to see how that turns out).
I have yet to find any pattern to what makes my cycles short or long. My longest was three months!
I get EWCM several times a cycle, but it stops after I've ovulated. My cervix is a good sign too. And both are cheaper than the useless OPTs!