Now I know this is easier said than done. But once you do it you will feel a weight lift off your shoulders I promise! I wish I had taken this advice wayyy sooner. If people treat you horribly, they in no way deserve your kindness or your friendship. This may seem like a no brainer, but trust me people make this mistake all the time (I'm one of those people, but not anymore!). Stop being that puppy dog who follows around that one friend or group of friends just to gain their approval or friendship. Friends are suppose to help, love, and support you, not bring you down! You are way better than that, you are awesome, and you deserve awesome friends in return of your awesomeness. Don't let someone walk all over you. Why should you be nice to someone who treats you like crap? Treat people the way you want to be treated!
You tell those mean people to talk to the hand and move on!
Tip: If the person who treats you like crap is your boss, do not use the talk to the hand method, I recommend, as my granddad always says, just to smile and nod.