Thanks for your query.
Delayed or missed periods can be due to stress
imbalance,PCOD,hypothyrpoid and even pregnancy
if you are sexually active.
I guess your doctor has given Deviry after ruling out any history of sexual activity.
Deviry is medroxyprogesterone
a hormonal pill to get withdrawal bleeding when periods are delayed.
You can take it and there should not be any problem.
Once you stop these medicine you will get periods in 3-7 days
Hope this answer is helpful to you.