What Causes Delayed Periods,pink Discharge And Sore Breasts?

hi im 22 yrs old, my menstruation is 10 days delayed, i always have my menstruation normal. Last week i got pink in my panty, i wipe it and then no more. Last thursday also i take pregnancy test and it was negative. But im having soar breast its hurting now much like an injection. What should i do? Dont you think im pregnant or not? Please help me