You had sex in your fertile window, and unprotected sex can definitely cause pregnancy
. But sine you had an i-pill within time it is less likely that you would conceive. I-pill has it's own side effects like irregular bleeds, disturbed ovulations and mood swings. Hence frequent use is discouraged.
Serum beta hcg
only give a probable guide of pregnancy.
The only best thing would be to wait and watch. If you miss your scheduled period this month, do a urine pregnancy test. If it tests positive you are most probably pregnant
, you need to consult a gynaecologist
If it tests negative you can wait for periods further.