Confused

Saturday morning I wiped at toilet and had very light pink blood on paper. Sunday afternoon had samething. Wiped in afternoon I wiped n got very light pink blood. Monday felt nauseous and sore nipples. Negative test. Nausea, cramping n sore nipples for rest of the week. What is going on. Anyone else had this. Period not due till 24th October as came off pill on 24th September. Could I be pregnant or is it my hormones due to coming of the pill. Have no idea when I ovulated. Help!!