@belay: If you are having a good time with her, and enjoy your relationship; then do not be paranoid. You should not care about the drugs and the other old boyfriend.

Although it is not nice for her to tell you to literally "stfu" about an important issue on your behalf, if she tells you so then remain silent.

Later on if it comes out to be that she does not really love you, then drop her.

You should not be so focused on the question of "her loving you". You should focus on if "you love her". If you love her, then you are enjoying your relationship and vice versa. If you do not enjoy your relationship then quit. Do not let it become like a tobacco addiction which you hate so much. If a relationship becomes a bundle of stress, then it is not the thing you are searching for.(Do you get the point? (do not be angered by this question, I am asking honestly)).

Take care and I hope she calms down and you two enjoy yourselves.