I have taken the Morning After Pill twice in the past. As far as I know you have to take it within 48 hrs of possible conception and like the others said it can make you feel nauseated.
If you are not ready to have a baby, and all of the responsibilites that come along with being a parent at this time in your life, than there is nothing wrong with taking the MAP, and nothing to feel guilty about.
The second time I took the MAP, it didn't work. My boyfriend at the time was wearing a condom and it broke and sure enough it was right during the time I was ovulating. I went to a clinic for the MAP the next day and took it as prescribed. Several weeks later I never got my period. I did two home pregnancy tests which were positive and finally a blood test, which did confirm I was pregnant. The nurse told me that the odds of me conceiving after taking the MAP were extremely low........but I did.
I hope everything works out for you.