Why do I have brown discharge?

So I have had a clear discharge for over a year. I have always been wearing pads and even though its annoying i still always wore pads. But now all of a sudden I got a brownish discharge. At first i thought I went to the bathroom and didnt wipe good or something but thats not it. I have never had this and its almost a reddish color but not quite. I have no had my period yet. The discharge is kind of icky gross and smelly. I dont want to start/have my period while im at school .-. I have had cramps but i dont know if its because im starting my period. Someone please tell me whats happening? ALso if I am starting my period could someone give me tips for school. Like what should I do if I have my period at school because the teacher dont always let us leave the classroom. Also I tried out tampons before but they are uncomfortable. Would you recommend tampons? Also when would I actually start it. Like would I all of a sudden have cramps and not feel good or something?