You can't get along with everyone. That's not possible. Not everyone is going to care about every little detail of your life and that's OK. The important thing to realize is no matter what happens, you always have you. The voice in your head that's constantly chatting it up can either be your best friend or your worst enemy. It may be difficult to know who's who at first, and that's why I made a handy dandy exercise to help you figure it out.
Start with setting a goal for yourself and list the challenges to reaching it. Divide a piece of paper into two columns labeling the left side "friend" and the right side "enemy." Look at your goal and its challenges, such as: the goal is to lose weight while the challenge to losing weight is eating fatty food. Under the "friend" side write any and all advice someone who cares about you would give, then under the "enemy" side write any and all advice someone who is against you would give. Once completed, read over what you wrote and decide which voice is the best choice to listen to in order to reach your goals. Remember, you always have you, even if you're your own worst enemy.
