What Are The Chances Of Pregnancy Having Delayed Periods?

hi--I'm using an ovulation predictor trying to conceive. My periods have been a bit irreg since birth of my son 3 yrs ago. Anyway, I found out ovulated late (wish I wrote down the day!) I think was 22 or 24 or something--but late. I am now on CD 41 or 42 and still no period, but getting negative hpt's. Could I still possibly be pregnant? having minor symptoms but nothing that would tell me I am really pregnant. No sickness, sore breasts,etc. Little nauseous rarely, and headaches, little constipation. With my son I didn't have any symptoms either though. Thanks!