Please do a home
pregnancy test first, even if pregnancy feels unlikely, since a missed period always needs that ruled out. If it's negative, the usual reasons for cycles like yours are hormonal changes linked to weight, ovulation that isn't happening regularly, and stress. PCOS can show up this way even without acne or facial hair, so it's worth asking about. Your
thyroid has already been checked, which helps narrow things down.
Next Steps
See a gynaecologist for an examination, a pelvic ultrasound and a few hormone blood tests, which together show what is delaying your periods. Losing even a small amount of weight gradually, through regular walks and simpler home meals, often helps your cycles come back into rhythm. Go in urgently if you get very heavy or prolonged bleeding, severe pain, or feel dizzy.