Thanks for your email. Depersonalization disorder (DPD), also known as depersonalization/derealization disorder (DPDR) happens when someone feels disconnected from themselves. The depersonalization, panic, and paranoia symptoms you are describing all seem to be pointing back to a shift in your sensorium that gets interpreted as a loss. In other words, each time you take a drug, or have an intense body sensation or feel dissociated from your body you are fearing you will lose yourself. Your description has three features I think deserve attention.
First, I would schedule an appointment with a neuro-psychologist, neurologist, or psychiatrist so that the entirety of your experiences (including the use of pain medicine and marijuana) can be reviewed. Secondly, once you have a better handle on what activates these experiences and why—I will encourage you to begin regular individual therapy so the process of talking and discussing these feelings can happen on a regular basis.