This is not a good advice. Some years ago I was in group therapy and a few members smoked weed during the weekends and some even outside the therapy. It wasn't allowed because the weed and also other drugs would make you feel different and make you not feel negative emotions. But they needed to handle those emotions in a different, more healthy, way.
If you keep smoking that, it could become an adiction.

She should help you to find other ways to cope with the pain.
You could try an anti-depressant or something. But for that kind of things you should ask your gp or a psychiatrist for advice.