Hi Andrew
You’ve made the first step admitting it and wanting to quit so we’ll done. My advice is don’t beat around the bush with quitting just pick your day and stop cold turkey that’s what I done, I was taking codeine for 10 years and like you it was N+ I’ve been stopped now 2 month and feeling great. When you stopped on holiday for the 7-8 days you will have been going thru physical withdrawals which is as you described the flu symptoms, aches and sweats but usually that’s over in a week so it’s a shame you went back on them when you got back but you just were not prepared by the sounds of it. I’m not exactly sure what advice you need/want but I’m happy to help any way I can I’ve been in your shoes and came out the other side and it’s totally worth it mate. How long you been taking them for and what is your current dosage ? Let me know and good luck