Hi , I'm 16 & sexually active . Last night , I felt I was going to throw up , I was dizzy , with a headache , and I felt weak . I woke up this morning , and I used the bathroom at school . I seen a brown spotting in my panties , I squeezed about 3 drops of blood out . I still feel a little weak. I am on birth control , but I've missed quite a few pills . Do you know what's wrong ?