Larson first off do NOT beat yourself up over taking that .5mg sub *THIS* is precisely the way us opiate addicts learn how to actually quit opiates. We try quitting a thousand different times, in a thousand different ways, and eventually if we are smart we refine "our method" down to something that eventually works.
I think the reality is simple. You took that sub because the transition was likely too hard or traumatic for your brain. You came off of dosing at a small amount, but you were still taking that amount everyday. Your body was USE to get sub everyday regardless of how much it was. I really really stress that with quitting opiates, one of the most important things is manipulating how much stress you are exposed to. If you are taking on too much stress for too long, and not actively trying to avoid triggers (like driving around with sub in your possession I can't tell you how many times I've snorted sub in my car) you are that much more likely to use.
However, if you break the addiction like Carl said, by dosing every 2-3 days, maybe even 4 days, very low amounts, it will be a shiton easier to stop. Less stress on those busy work nights. Less ruminating over every single sucky aspect of your day. The stress slowly builds up and the second we are faced with any remote trigger, we will use.
You can go back to full blown using. Or you can go back to strategic dosing and revise a new method. I understand how intense the desire is to just want to stop and get shit over with... but really why are you in a rush to stop? If you were able to dose say .10mg, every 3 days, for the next month... then stopped after that I imagine it would be a breeze to get on with life.
We have cravings switching to sub cause it doesn't hit our receptors quite like the full agonists. But we *stablize* over a couple of weeks and the cravings go away.
Same with tapering. I was at 5mg a month ago. Am at 3mg today. Every time I drop my dose I have cravings to use for about a week. After that my body adjusts and I'm ready to drop again.
With quitting, I really think even if you are taking like .01mg a day, just because you are taking it everyday, its still going to be hard and you're still going to have cravings if you stop 100%. And that final stablization period can take a lot longer before you feel better. Very much like the tapering drops. But opiate addicts I think are really too cocky and thats what always fucks them in the end. Do not just assume you should be able to tolerate coming off the dose you did.
Can you? Yes. But look at life objectively. You have work, you have a gf, you have many different roles you must play, all of which are stressful even if you weren't coming off opiates. So I say make that transition as smooth as you possibly can, and you will be that much better off.
And I've said this before but quitting an opiate habit is like landing a plane. Sometimes the wheels touch the runway (the days you don't use) but they don't just hit the runway and stay on the runway. They bounce up and down a bit untill its a smooth ride. Use this to your advantage and intentionally bounce your wheels. Don't try stopping all at once and expecting a smooth ride. Really man all you would need is like 1 more 8mg sub. Cut that shit down into .1mg strips, then just put them under your tounge every few days. It will become easier and easier to stretch the days like Carl said.
I REALLY think if there is any painfree way of stopping sub that would be the way. Be realistic with yourself it would make life so much easier.
Last thing. Clonidine helps A LOT for opiate wds. You will see some people say it didn't do much for them, and the reason is simple, doctors underprescribe it severely. They give opiate addicts the same amount they would give to a person with hypertension. But opiate wds are wayyy more intense than hypertension. If you can get your doctor to raise your dose even just 150%, it would help a lot with anxiety cause thats what its all about. Control the stress, control the anxiety, be as strategic as you fucking can. Consider yourself a green beret at quitting opiates. It will only benefit you in the end.
God I can't wait to get under 1mg of this shit again. Cause I'm telling you this time I'm not fucking around. I'm doing this jump off exactly how my brain tells me. If its telling me it needs .0001mg of sub, I'm giving it that. As long as I'm always going down in my use thats all that matters. I have no specific day mapped out for quitting and I don't think people should. You quit when your brain is ready. Respect your brains biology, that shit is sensitive as fuck. But I really think you can do this man just focus clearly and understand what works and what doesn't.