Burning and stinging when you urinate, especially with the light pink spotting, most often points to a urinary tract infection, which is common after unprotected intercourse. The i-Pill itself can cause spotting and some stomach upset, but it doesn't usually cause pain while urinating.
Next Steps
Get a urine routine and culture test done, which will also screen for infection and your
sugar levels given the unusual smell you noticed, and drink plenty of water. Taking the i-Pill within 3 to 5 hours gives it a good chance of working, though emergency contraception isn't always fully effective, so take a home
pregnancy test if your period is delayed.
Health Tips
See a gynaecologist soon if the pain worsens, you develop fever, or the bleeding becomes heavier than light spotting.