You got withdrawal bleeding after taking unwanted 72 pill. It is quite common and natural phenomena. However, it doesn't mean that effectiveness of the pill alters without withdrawal bleeding.
As you took the pill within 1 hr, you will get more than 95% protection against unwanted pregnancy
. Your next period may be delayed for 1 -2 weeks from due date due to hormonal
I suggest to undergo one home pregnancy test if period delays more than 1 week. Next time, you should take regular contraceptive
pill instead of emergency pill.