Everyone is different. I can smoke weed with ten other people and be the only one negatively effected. I've also been the one not negatively effected while another person is. Everyone's bodies are different.

I've had best friends for 7 years, I even paid their portion of the rent when they were on hard times. I've even fed these people because everyone has their bad moments and I loved them. They ended up screwing me. It reallly sucks, but as people grow they change.

It she means that much to you then try to express how you feel in a heart to heart, it's really all you can do.