thank you for your query.
Firstly,having sex just a day after your periods anyways has a very less chance of resulting in a pregnancy
, as ovulation has not occurred.
ALso you have immediately taken the I pill
so it should confer added protection.
Yes, the I pill can interfere with your menstrual cycle, making it come earlier or later.
Also, you should not regularly take I pill, it is not a substitute for contraception
Please do not freak out, because I pill will not permanently disturb your hormones.
At the most, it will delay your period by a week or so , not more.
You took the pregnancy test too early, it would not be positive so early even if you had conceived.
Right now, wait for a week, if you do not have your periods, take a pregnancy test .