Hello
im so sorry to read this, it’s so awful when you find out that the person you fall in love with isn’t really the person you fall in love with as they lie.
do you think the chatty outgoing girl you met was clean of drugs or used when she met you?
you said you had the conversation about drugs and how you feel about them however she still used on separate occasions.
they are good at lies they tell you want you want to hear. I don’t think if she is still going out with friends that use that she doesn’t on a night out.
if she wants to be with you and you need to trust her perhaps she could do drug testing for you or something similar to prove that her love to you means more than the drug and will test the following day after her night out ? Then you can build the relationship back up from there?
I hope all works out for you and you find a way of communicating and trusting her and she proves that her love for you is stronger than the pull of the drugs.
take care
navy x