To answer some above questions:
My cycles are very, very regular. This last one was the same. My ovulations strip instructions also say that a faint line is not a positive but I have used this brand to conceive three times and I've never, ever had a dark (positive) ovulation line. Never once and I test every single day at the same time when TTC. So I KNOW I had a positive ovulation day in there somewhere, otherwise I wouldn't have these kids!
I wasn't keeping track enough to know how long it usually is between my period and my ovulation, but, my bodily signs over the last year or so give me the impression it is always about 2 weeks as it should be. My CM went through all of the normal phases each month. Wasn't taking BBT and I don't normally do ov strips unless trying to conceive. (Have only had to use them one cycle each time I've gotten pregnant so I don't have several month's worth to track.)
Haven't read Taking Charge of Your Fertility but have heard nothing but rave reviews. I don't know how people read books when they have little kids!

If it's on audio book I may look into it...although once I figure out my due date I am not so interested in fertility anymore. This is DEFINITELY our last!

But maybe it would still offer a lot of useful insight about my cycle regardless. Thanks for your help ladies! I will see what the doc says about a dating ultrasound when I see him on Monday for my kids' checkups.