First of all, this questions should be asked to a doctor or pharmacist in whom you can trust. Information obtained on the internet can be incomplete, may not apply to your case or may be utterly false. That being said, maybe this can help you:
By your question I understand you took an emergency oral contraception pill. Most common drug in these products is Levonorgestrel, contained in Plan B and Next Choice brands. If this is indeed the drug you took, the breast tenderness can be an expected side effect. Taking these drug 69 hrs after unprotected sex is still in the 72 hours range given as safe, but only for a small margin.
Your period is altered by the drug (it's a hormone analog) and will be irregular for a few weeks.
---TALK WITH YOUR DOCTOR, as he or she may determine if a pregnancy test is a necessary precaution ---