Thanks for reaching out to us! It sounds like you are going through a really tough time! You should definitely be proud of yourself for having so much strength to not do drugs. Even though it might seem like your friends are having a good time doing drugs at these parties, they are harming their bodies more than they know and can even imagine.
Drugs can reek havoc on a person's body--they kill brain cells, put you in danger, there is always the possibility of overdosing, even ending in death. That doesn't seem like something that's "fun" or good to do. There's a reason that drugs are illegal--because they harm you more than they help you. Don't waver in your decision for one second to stay away from drugs. Good job on your part!!
It sounds like these people aren't really your "friends." Unfortunately, drugs can alter people's moods and even their personalities. It might be that these people were good friends before, but where they are in their life now is not a good place to be. However, if they are calling you names and put you down, then that's not a real friendship.
Friends should be there to support, trust, respect, and encourage you--not to put you down. If these people were good friends, then they should respect your decision and be there to support and encourage you.
It might help to talk to them about what's going on, calmly and respectfully, and let them know you are concerned for them since drugs aren't the best things for them, then let them know that as friends, they should be there to respect and support you.
As hard as sounds, it might be the best thing to focus on yourself and making new relationships and friendships--ones that build you up and don't tear you down. Try and talk to some classmates (if you're in school or college) or people you work with, and see if they'd like to get together to study or do something fun.
Another good place to meet people is volunteering or in places you might like to hang out--coffee shop, gym, library, park, etc. Ultimately, we can't control what other people do and say, we are only in control of ourselves.
As long as you are acting in way that makes you proud of who you are, that's the most important thing. Keep doing what you're doing and stick to your decision!! Hang in there and hopefully, the situation will get a little bit better for ya!