Anovulated?

Can an ovulation become an anovulation? I clearly ovulated last month according to my BBT chart. This month things were looking great. I started seeing a pattern repeat from last months. I got excited cause I ovulated again. And then, my temperature dropped slowly day after day going back to my preovulation temp. I'm supposed to start next week and I clearly already know I'm not pregnant. I can see now why OPKs don't do the trick. And I thought I was doing so great using those! Wish someone would have told me why doing a BBT chart was so important. I still haven't had it explained to me yet. I'm guessing that this could be a sign that one of my tubes is open, while the other one is closed. Which makes me worry that the HSG test will end up higher on my doctor's list of things she wants us to get done. If one of the two are closed, though it sounds like a 50% decrease in our chances of conceiving, I already know that is not true. Unfortunately which side an egg comes from each month is completely random. The side that may be closed could release an egg 11 times in one year, only allowing one month I could get pregnant. Or it could release one 3 times in a year, or maybe none this year at all. If I happen to have one tube closed who knows how much it could affect our chances. I am very distraught about this. I thought I was ovulating great. I would use those little ovulation test strips and get a positive every month. Then my first month of taking my temperature for my basal body temp chart confirmed that I was ovulating fine. But then this month... I'm so confused :\