Worried about pregnancy

Patient: HiWhile with my husband -sexually – the condom came off and I am woried about being pregant. I am on a cycle between 23-28 days. My last period was on March 7 (at 23 days after the feb menstruation) and the intercurse was on Mar 10. It seemed that the vaginal discharge was different the day after intercouse – could I have been ovulating – could I be pregant.?How effective is the Plan B or IUD insert – do you think I need either one?Worried – please advise