Welcome to HCM.
You did sex on 8th & 9th Sept just after 8 days of your last period and on 21st Sept.So your last LMP was probably 30th Aug or 1st Sept.You also took Unwanted 72 pill within 24hr.
Your period due date is 30th Sept.So ovulation occurs around 16th day. You did sex almost in safe period or non-fertile zone with taking extra precaution like Emergency pill.
So chance of pregnancy
is almost nil.
Your red vaginal discharge
is probably due to withdrawal bleeding of emergency pill and not actual period.So wait for your coming period.