delayed ovulation

I was just wondering if anyone has experienced delayed ovulation, resulting in a delayed period, due to stress. Some sources I've been reading indicate this would only be possible due to significant stress like a death or something. I've recently cranked my working hours up to 65-70 hours per week, I'm a student nurse on placement, plus I work a full time job too and travel up to 4 hours a day. Do you think that this Would this be considered enough stress to delay ovulation? I'm on day 39 and still no period, although I am sure I ovulated about 10 days ago. I'm normally quite regular from 29-31 days. I only just came off birth control in Feb as well. Do you think that this would be anything to do with it even though I've had normal cycles since?