I only really get fertile CM as I'm about to O and then maybe for the day or so on O. Then it changes and disappears altogether, until AF (or not, as the case may be!). CM is hardly there at all more than two days or so before O (and it changes to the fertile stuff only right before).

I think that's within the realms of normal, although I do have a shorter luteal phase than the optimum (not that's impeded my fertility at all).