Ideally post coital pills are to be taken within 72 hrs of intercourse but can be taken after 5 days also. Since you had taken the pills within 72 hours, so chances of pregnancy are very less. If you are apprehensive regarding pregnancy then you can get it evaluated. To confirm the status of pregnancy, I suggest you to test for pregnancy by a highly sensitive pregnancy test 10 days post ovulation with a sensitive ( 20 - 25 mIU ) pregnancy test. Also then I would suggest you to get your serum HCG levels estimated since this is more specific than urine for pregnancy tests.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
Thank you for your help. I ended up getting my period yesterday, so I was very relieved. If I experience any other unusual symptoms I will definitely consult my doctor.