Honestly, wellbutrin helped some for me, but the only thing that really seemed to cure it was forcing myself to do things I once enjoyed until I learned to again without heroin. That was one of the main obstacles of my addiction - after a while I used it before, during, or after everything to the point I got accustomed to it and nothing seemed as enjoyable without it. It sucks, but its one of the reasons they usually try getting you into gym, yoga, and shit in rehabs.
Or I also started trying a bunch of new activities which helped some, prolly cus I hadn't programmed my brain to link those activities with heroin.
Time above all else. I don't know the extent of your habit, but PAWS can last upwards of 2 years. I quit for a few years at one point and honestly it took me a year or so before I enjoyed shit almost as much as I once did. With the extent of my habit and usage of a list (a literal list of drugs even other addicts in iop thought I was crazy) I feel that I've permanently damaged my brain in some way cus even after a while I still have a degree of apathy and anhedonia I didn't have prior to my usage - even with the wellbutrin that I started after I quit.