I've been having light brown , dark brown and red blood spotting. since march 2014 . but no full period and sometimes i get cramping. what wrong ?

Need evaluation: The symptoms you are describing may ultimately be minor. However, they may be representative of one of several serious problems. The worst would be a tubal pregnancy, while an abnormal pregnancy or ongoing miscarriage are also possibilities. A urine pregnancy test will not be reliable in these instances. Medical evaluation is needed.