Im 20 yrs yes im sexualy active w my boyfriend and we dont use condoms bcuase im on birth controls (shot) ive been on the shot for 3 yrs now...my question is why did I get my period 10 days early??? the first day I just spotted one time the whole day the next day my blood was brownish w a little red yes its (regular-heavy)...i dnt have that much cramps just my lower back hurts...its this normal???