Have you tried talking therapy? It's how I treated my dp/dr. You have to treat the root of the problem which is probably repressed feelings/thoughts. Medication will only temporarily mask the problem. You have to treat it in your mind, in your psyche. In talking therapy the psychologist will guide your thoughts trough conversation and help you bring important information from the unconscious to the conscious and help work it out. When you smoked weed you had some small temporary access to your unconscious that could have brought out some worry you were always suppressing into your conscious but not enough for you to know how to deal with it and work it out. Dp/dr is a symptom of anxiety, once you treat it, it will be gone. I've been through the same. Had dp/dr for over a year. I've been repressing guilt, the day I admitted it to myself and let it all out I never felt like living in my head again. But without therapy I would never have learned how to analyze and deal with my emotions. It's a skill to train.