A glutathione supplement isn't known to delay your period or change premenstrual symptoms. Breast tenderness before your period can vary naturally from one cycle to the next, even without starting anything new, so its absence this time isn't necessarily linked to the tablet.
Next Steps
Keep taking the tablet as planned and track this cycle. If your period hasn't arrived by early November, or this keeps happening, see your gynaecologist to check for other causes.
Health Tips
Stop the tablet and get checked if you notice unusual heavy bleeding, severe cramps, or any skin reaction.