I don't think I'm ovulating!

I have been off BC for for 10ish months now and we have been TTC for about 8 months. Only this month have I actively been using OPKs and when I thought I was ovulating according to my CM I tested twice a day just to be sure I didn't miss it and I haven't even come close to looking like even getting a faint line! I'm worried I'm not ovulating! 
My sister and my mum are both highly fertile. Like me and my sister were conceived while mum was on the pill and my sister has conceieved 3 babies in the first or second month of being off the pill. Mum keeps telling me that I will fall pregnant quickly when we start trying (she doesn't know we already are). 
I've got long cycles, between 40-46 days since I came off the pill. I'm going to keep testing for the rest of the month and hope I get a positive. Going to have to go to the doctor I think. Any advice?