I haven't had period in 5 months and i'm not sexually active should i be concerned?

Yes: Please see a dr.You may have a myriad of problems-all of which require investigation.

Yes: This isn't normal so you should get it checked out. Although some causes of amenorrhea without pregnancy are relatively benign, some are more serious. Stress can cause amenorrhea, but so can polycystic ovary syndrome. You might have an eating disorder or hypothyroidism. There are many causes, with good medical treatments, so best to get this evaluated soon.