I am not an expert on opiate use, I have only used them for pain or about 20 times in 5 years for pleasure, and am neither a stimulant guy, I just started ADD meds 4 months ago but the dose is 5mg, now 10mg dexedrine a day. What I know altho is biochemistry, and how it interacts with our actions.
It seems like the shot pushed you in a situation where drug euphoria isnt possible anymore, (if I read right you still get side effects of stims right?), but when having fun in real life you are not blocked from feeling good. I would use that.
During the time you are on that shot, think of every drug you want to take and try to replace each of them with an activity that makes you feel similar. Sure it will not be as intense but it will be better than wasting money on drug's side effects.
Also you could consider talking psychedelics to learn how to appreciate life sober more and more as it is a long term effect of psychedelic use.
Psychedelics won't replace the drugs but they might amplify the fun you get from the activities that are used to replace the drugs hence making you less in desire of using drugs.
Overall what I am saying is: if drugs don't work, give up on them for the time you are on that shot. Replace them with activities that makes you feel similar.
And using psychedelics spiritually or as a sobriety amplifying drug would make those said activities feel more intense and better. With both you might be able to get rid of any desire to do drugs and replace it with a desire to act, have real fun, and trip, to make the real fun even better.
As for your sex drive, it will come back with time, IDK how long because its dependant on the dose you took when addicted the duration of addiction and your body's ability to come back to homeostasis regarding hormones which takes longer than normal Neurotransmitters. But be sure that being free from opiates it will eventually come back fully.
Good luck with managing that, and I hope you will find a way to have as much fun that you had on drugs , but sober.