Hoping mother nature isn't being cruel!! advice/reassurance greatly received!!

Im usually regular 28day cycles, and am now currently on 4th day of late AF. This was my first month using opks and my +opk came on day 22. So I dont know if I ovulate this late in cycle all the time or just this month and whether late ovulation is causing delayed AF or could I be pregnant? only flaw in that is no symptoms and continuous BFNs since saturday when AF was due. Any advice ladies?