Thanks for writing to HCM
There are very less chances of pregnancy
pills are highly effective(up to 98 %) if taken within prescribed time.
Your symptom may be due to some other reasons.
But if you have doubt,you should wait up to next menstrual period .If you misses your next period then urine pregnancy test should be done.
Generally,Urine pregnancy test is done after missed period for confirmation of pregnancy,but Ultrasound
of pelvis is the investigation of choice for confirmation of pregnancy.It can detect G-sac earliest.
Hope i have answered your query.