best way you can tell the date you ovulated is 14 days prior to first day of cycle. but stress can delay a cycle as well. if your regular and your cycle returned to 28 days i would not worry about the late cycle. i am not sure if tis helped but hang in there.
Stress or traveling can certainly delay your ovulation. Typically your luteal phase will be about the same each cycle, so if your O date gets delayed, your cycle will be extended. Now that you're back to a normal schedule, you should go back to your typical cycle length. Good luck! :)