I have unprotected sex with my gf on 5 March and taken unwanted 72 pill with in 4 hours,  withdrwal bleeding effects 11 to 12 March, I have done Beta HCG on 13 April which was negative after 39 days of intercourse, and pelvik ultrasound which was also negative after 49 days, light spotting with starts from 13 April and countine till 23 April last colour change black to red as period, is this was my period.. Is any chance of pregnancy..?