Condom failed, took plan b within the hour. two days later uti like symptoms and expected period was very light but extremely dark brown.

Plan b: Plan B can cause changes in menstruation. It can cause your period to be heavier or lighter earlier or later. Other symptoms include nausea, abdominal pain, fatigue, headache, dizziness and breast tenderness. Painful urination, is not associated with it and if it persists a urine culture should be done to rule out a urinary tract infection.