What Causes Stomach Bloating Nausea And Abnormal Vaginal Discharge?

Since unprotected sex, I have had yellow-white mucous like discharge for a couple of days now, just yesterday i started bleeding a little, not enough to be my period, just more like spotting or something. It was different though, it was pink and light. Today I am having brown vaginal discharge, it is not foul smelling, just like a mild odor. I do not start my period for another week.. Just a couple weeks before, I felt bloated, I craved pickles, ate like a pig, I've felt nauseated, I've been cramping, and I have had weird food cravings.. could I be pregnant, or am I definitely pregnant? The problem is I am on birth control, and I haven't stopped taking it because I thought that the problem would go away, i need help on answering this question.