How do people get away with it?

So recently i unintentionally got help with an assignment and was suspected of ';cheating'; the donkey teacher prolly took it to the dean and head. But my best friend, who i love dearly, she gets away with everything. She cheated a full course, got tests from a friend who previously took the class and aced the exams while the smartest people were getting like Bs, she was getting As. Then whats worse, at a school assembly she gets recognized in that VERY class! I cant handle it. But she is my best friend, and has been there for me alotttt. Everyone loves her now, and now some look at me like im the bad guy because of 1 assignment, not even an exam, a homework! I dont get life, im frusturated and dont know how to feel or what to do. I feel discouraged and its my last semester of senior year and i feel unmotivated. What do i do?How do people get away with it?
even though that is your best friend you need to realize there will come a day when everyone finds out what she is and has been doing all this time regarding school and her grades. and she will look like the bad guy. so dont worry too much about that. becuse it is your senior year and your last semester i suggest you basically ignore it and carry owith the way you have been doing things. dont cheat, just try your hardest. and before you know it the year will be done and you will be off to college. and life continues after that. dont get unmotivated you are almost to the end and why give up now . good luck