Thanks for your query.
Yes, stress could be one of the causes of delayed periods.
Other causes include, hormonal
imbalance, emotional disturbances, ovarian cyst
, thyroid problem,excess weight gain/ loss.
I suggest you to get your blood tested for beta HCG.
also helps in detecting early pregnancy
Once pregnancy is ruled out, i suggest you to visit your Gynecologist for complete physical examination and relevant investigation.
Do not worry as all the above mentioned causes of missed periods are treatable.
Hope this helps.