Missed my pill (don't normally get a bleed) had unprotected sex - abnormal bleed/dark brown ect. Dizzyness, tired feel sick negative pregnancy test?

Missed pill. If you missed only the one pill and did not have sex during your ovulation time, you may have still been protected. The color of menstrual blood makes no difference -- "dark brown" blood is most likely deoxygenated, but still comes from the inside of your uterus like all menstrual blood does. If you've missed more than one pill or took your pregnancy test before the bleed, please re-take.