Friendships and relationships should not be hard and should not be stressful. If the people you surround yourself with are causing negativity in your life, it is time to re-evaluate why you allow yourself to associate with them in the first place.
Know your worth. You do not deserve to feel like you are not good enough, because you are worthy of so much more. There will always be people who will go to unnecessary lengths to bring you down as a result of their own insecurities. Even if this is your best friend that you have known since you were six years old, it is time to let go. This goes for relationships as well. If your boyfriend of five years suddenly stops treating you like the princess that you are, it's time to let go.
Quality over quantity, always. Deciding to cut people out of your life that have been there for so long is often difficult and heartbreaking. We get so used to these people and the toxicity they bring because being around them has become comfortable. But, it comes down to the fact that they do not deserve the privilege of even being in your life if they are not contributing anything beneficial. Friends are supposed to be supportive through the ups and downs. It is better to have three friends that are truly interested in your well-being than ten who could not care less.
Letting go is tough. If the people you surround yourself with are not making you want to be a better version of yourself and/or are not supporting your growth, move on. Do away with the pessimists and the selfish people because they are only bringing you down. Know that you deserve so much more than upsetting friendships and relationships. People change, sometimes for better and sometimes for worse. Or maybe they are stuck in one place while you flourish and thrive. It's one of those things that's just out of your control, and that is okay. You cannot control the way people act, but you can control the people you share your life with.