Thick white discharge along with itching and some swelling near the vaginal opening usually points to a yeast infection, which is common and very treatable. A period that's a couple of days late after being sexually active can also happen from a mild infection or hormonal shift, not just pregnancy.
Next Steps
Take a home
pregnancy test since your period hasn't started yet. Keep the area clean and dry, wear breathable cotton underwear, and avoid scented soaps or wipes until you're seen.
Health Tips
See a gynaecologist soon if the swelling or itching gets worse, you develop pain or fever, or the
pregnancy test comes back positive.