Period 7 months late! Could there be something wrong with me?

Hey I'm 13 years old and when i had my first period it was in December. It lasted for 7 days but was a wierd brown color the whole time. I had another period like that a month and a half later. But now its been 7 months and I still havent had my period again! Today I started getting like brown discharge all of a sudden. Do I need to go to a doctor since I havn't had it in 7 months or because its always brown? HELP! I'm so confused and my mom doesn't want to hear about it! :-(