Since you have taken prostinor and have got bleeding after that,less likely that you would be pregnant but depends on when you took prostinor it has to be ideally within 72 hrs of unprotected intercourse
. But it cannot be ruled out so wait fir your next period or else get a sonography
done to confirm your doubt. I would advice you to use proper contraceptive
methods rather than using emergency contraceptives as they too harm your body to an extent.