So, good news and bad news.
Bad news... depending on how long and how much you were using, 3-6 days in might not be the worst. For me, usually somewhere around 4-8 days in is when things got really ugly. Things start to calm down and level out around day 10-14, although if you're using opioids like methadone the acute withdrawals can persist for 30+ days is what I've heard people report.
Good news... using again doesn't "reset" the withdrawal phase. So long as you don't start using daily again, you'll still be on you're way off. Some "taper", or slowly reduce their dose, to make withdrawals less intense. I wouldn't advise trying to taper off opioids because of how hard it is to control yourself, but just know that one use doesn't mean failure. It's not so much a relapse as it is you struggling to get it right, and mistakes are not the end of the world. At this point in your recovery, I wouldn't get hung up on that word too much.
Also, some more good news(at least in my opinion), there is no such thing as "addictive personalities". It's a commonly used term that is NOT recognized and accepted by the world of science and psychology. Addiction is a biopsychosocial disease, meaning it affects your body, mind and the world around you. There are genetic components that can make someone more or less predisposed, but this is just one factor among many. Who YOU are, how you were raised, where you were raised, in what culture you were raised, with what culture you identify with, your socioeconomic status, your friends, your friends parents, etc. are all potential factors just as much as who your parents are. No one is born an addict unless your mother used drugs while pregnant. And even then, I'd argue they are not an "addict", but instead addicted. We HAVE problems, we are not our problems.
Like most, I'd imagine that you weren't always the way you are now. You even mention a time that was better that you'd like to return to. In the same way that you didn't get to where you are overnight, you won't get back to where you were overnight. One of the hardest things to stomach for me was accepting how much time I had wasted, and how much time I must spend to get back to where I once was. I know when you are fighting cravings it can seem like recovery is just about overcoming the urge to use. And it largely is, at first. But the real work comes with things like relearning how to deal with intense emotions and not just ignoring them. Your thoughts will still be bouncing around in your head, and left unaddressed they will drive you into madness. Listen to the way you think and talk to yourself. Negative self-talk is extremely common and extremely hindering. It's not uncommon to think that you have to mentally beat yourself up as punishment for making a mistake. The truth is though, this does nothing to further the solution or rectify the problem. It only makes things worse by causing things like anxiety and self-esteem issues.
TLDR: You're going to be ok, you have a rough ride ahead, but you can make it. You can look into "comfort meds for opioid detox" if your situation is unbearable. Make sure to stay hydrated- Gatorade, Pedialyte, and watered-down sprite is what I drank personally. Get easy to eat and easy to prep food. Canned chicken noodle soup, cup noodles, rice, bread, those sorts of things. Shit you can eat when you are dead sick with the flu. You are basically treating yourself for a severe flu for the next week or two. How showers, short walks, Netflix, youtube, and podcast. Give that mind something to chew on while its turning over and over. And something that can't be stressed enough, human connection. It might be time to come clean to your family and friends.
Isolation is often what keeps us from moving forward. If nothing else, keep us posted on what is going on. People care, and you are worth it.
