Thanks for posting your query.
Post coital emergency contraceptive
pills like I pill or Pill 72.are to be taken within first 72 hours after unprotected intercourse
. You have not mentioned whether you took them within 72 hrs. These can be the side effects of the pills but if you have taken them after 5 days of unprotected intercourse then chances of pregnancy
You can do home urine for pregnancy test after 1 week- 10 days of your due periods date. Urine for pregnancy test depends upon the particular level of hCG in the blood. So sometime it may be possible that it can give you false negative results during early days of pregnancy only because of un- sufficient level of hCG to make test positive. Hence it is better that you go for blood test
or an ultrasound
uterus which will give you more confirmatory diagnosis of presence of hCG and pregnancy.
Hope this answers your query.
Wishing you good health.