if you took the postinir within 72 hours if intercourse, it is almost certain that you are not pregnant. since he didn't ejaculate inside you, it is even less likely. so I don't think you need to worry about pregnancy
. it is also common that postinor will cause some irregular bleeding that may last a few weeks. however, if it has been months since taking the postinor, your periods should be normal by now.
I hope this answers your question, please let me know if you need any more information.