There are no guarantees when it comes to unsafe sex. If you expose yourself to semen or pre-*** (which can contain sperm), you risk pregnancy and infection. I can't tell you 100% that you're not pregnant; although it seems unlikely, especially if you took a morning-after pill and began to bleed. If you DIDN'T begin to bleed, that means the pill wasn't effective, and you should go to your nearest women's clinic or Planned Parenthood for an exam.
Your best course of action now is to educate yourself about risk reduction and either avoid contact with semen and pre-*** or decide upon an effective pregnancy/risk reduction method that works for you. See the birth control and risk reduction health information pages on this site. Remember: with great sex comes great responsibility. Best of luck to you. Dr. J
No, you should be in you safe period 3 days after Menses... You are fine with regards to your explanation, just try and play safe next time.