Hi there and thanks for your letter.
It sounds like you are worried about how you are behaving when you are with these friends. I get a lot of letters from young people about peer pressure. I know it can be really difficult to behave in the way you think is right when you are with other people.
Sometimes we think we will have more friends and be one of a gang if we behave in a way that doesn't feel comfortable. It can be a difficult choice to do the right thing.
I wonder what might happen if you told you friends you don't want to do this anymore? Do you have any other friends you can spend more time with?
Why don't you post this problem on the ChildLine message board then you may get some advice from other young people?
I hope this helps
Take care
Sam