Period is normally heavy and lasts for 5-6 days. This month I only had brown discharge which lasted for 1-2 days. Could I be 15 & pregnant?

Pregnancy. Have you had unprotected intercourse? The character of your menses can change depending on whether or not you ovulated. At fifteen the regularity of ovulation has not been well established yet. Even at an older age you still do not necessarily ovulate every cycle. It is time for you to have your parent take you to a gynecologist to get contraception and to gain an understanding of your body.