I hate answering questions like this. One of the reasons being is that there is still so much that we do not know about.

By chance did your girlfriend have a past drug problem or possibly a special relationship with her friend?

Please give us a little more background. How long have you know her. Did she or does she have a drug problem. Is she really touchy feelly   around her friend. Has her personal hygiene habits become sloppy?

Try to give us as many details as possible and we will try to help.

Good luck and best wishes.