Hm, I'm wondering if suddenly changing schedule of waking up can cause delay menstruation? Well, I usually have late menstruation (for example, I had my period on August 8, then last month, I had it on September 11--- waking up every 5:30-6am). Then this month, I suddenly changed my working schedule---waking up every 3-3:30am---and now, I still don't have menstruation, I was expecting to have it on October 11-15, but I still don't have it. So, is there a possibility? Thanks