I'm 18 and have been on birth control for about 6 months now. My period is due in a week but within the past two days I've started cramping very badly and been spotting. The left side of my lower back is also in a lot of pain. I play volleyball and am constantly putting my body through a lot for it. What are the chances I was pregnant and am going through a miscarriage, or am pregnant or what? Please help /: