what could be wrong?

i have always been very regular with my periods, until the last 8 months. the time in between seems to be getting longer and longer for instance they have went from 23 days in between until now, and i am on day 36. my last period was august 28 and i have not had a period since, that one only lasted 2 days and was very heavy. im wondering if maybe i have some kinda hormonal problem, or if it could be possible that im pregnant. my husband and i have been trying for about a year and im 20 years old if that helps....any responce is greatly appreciated!