Hi there, I have understood your concern. I will suggest you the best possible treatment options.
First of all do not panic.
As you might be aware that in a woman with regular cycles day 10 to 20 of the cycle is the most fertile period of cycle. If you happen to have unprotected sex act in the fertile period, then you stand chance to get pregnant .
As you have mentioned that you had unprotected sex act a day after your menses, chances of getting pregnant are almost nil.
Secondly, when you have unprotected sex act with penetrative sex and semen ejaculation inside the vagina, the actively motile sperms immediately enter inside the womb. So pushing out of semen will not help to prevent the
pregnancy, when you are in the fertile period of cycle.
So please use suitable
contraceptive method like condom to prevent the unwanted pregnancy.
Please get proper sex
counselling done before hand.
I hope this answer helps you . Thanks.
Dr Purushottam Neurgaonkar