Question for Betty.
My periods are very irregular and I can go a few months with a regular period and a few months without one, etc.  I had unprotected sex and according to my period tracker, I'm on my last day of ovulation.  I took Plan B about 2 hours after I had unprotected sex.  If I'm ovulating, does Plan B even do anything?  I'm really scared and worried that I may get pregnant.  At the same time, since my period is always irregular, who know if I'm really ovulating or not.  Thanks so much.
Betty's Answer.
You have a very valid question, and are right to be concerned.  Having unprotected intercourse exposes you to potential pregnancy and to sexually transmitted infections (STIs).  Using condoms will greatly reduce your risk.  It is very hard to know when you are ovulating, even when you have regular periods.  Plan B was an excellant choice especially since you took it within 2 hours of intercourse. 
There is something else you can do.  While you are concerned and motivated, you can make an appointment with your health care provider, or the Student Health and Counseling Center, if you are an eligible student, for contraceptive counseling. 
It is important to start on a reliable method of birth control.  We can do a pregnancy test 7 to 10 days after unprotected intercourse. Relying on a period tracker for safe days will result in you getting pregnant.  If you have any further questions, contact the Student Health and Counseling Center at 907-786-4040.