I mean, I am not sexually active. I am a 30 year old virgin been regular now for 9 years and now all of a sudden I am irregular like I was in college. What's wrong?

Any major changes recently? Illness? More stress than usual? Substantial changes in weight?

If nothing new has occurred, and even if it has, best to see your doctor. Missing a period here or there is not altogether uncommon, but when you miss some in a row, after normally being quite regular, it should be looked into.