Brown discharge. Am i safe?

Hi..I have irregular periods lmp 20.3.2016 usually 40 or 45 days.on 5.04.2016 I had unprotected sex did not ejaculated inside but outside vagina.confusion occurred so next day exactly after 16 hours of sex I took unwanted 72..after 7 days of unwanted 72 ...13.04.2016 I got bleeding for 3 days 1st day normal.other 2 day light bleeding with clots...after 1 month passed I did not periods so I took meprate 10mg 2 times for 5 days 15/5 to19/5..l got 2 drops bleeding on 25.05.2016 after 6 days of taking meprate.from 26/5 to today brown discharge sometimes few drop blood passing...I had hpt test in 30/4 ,12/5,16/5,26/5 with morning urine all r negative...I had whole abdominal usg on 16/5 exactly 41days after sex said left overy functional cyst.i had beta hcg test in 27/5 during my brown discharge/ periods which measure 2.00mlU/ml is there any chance of pregnancy..I am in a stressful conditions from 5 th April can'tcalm down plz help me asap...am I safe???