Can this be explained?

[Jabberwocky]

Ok, so this is just a follow up question based on the last question I posted about mentally wanting more oxy. The question I'm dealing with is last year around this time , I had gotten out of rehab, not for a true addiction compared to others stories but i milked my insurance cause I didn't have anywhere to live at that moment anyways I had gotten a root canal done and was given codeine 3's which have about 300mg Tylenol in the along with 30 mg of codeine. I took 2 of them to start my day and as the day went on I begin feeling very lethargic and every time I sat down I felt as if I was going to nod out and in my mind I thought I was to die. It was a very weird feeling, that I ended up stand up and staying in motion just to keep myself from nodding out. That being said I finished the script at half the dose no problem. The next month I began getting some kratom called train wreck mix bag, I never measured the doses so I don't know how much I was taking but it gave me the same effect but totally stronger but ever since then its like my tolerance has went down with opiates to the point where I cannot take more then 5mg of oxycodone without a feeling of malaise and not enjoying my time. This is odd, because even in my hay day with oxycodone I was taking maybe 15 to 20 mg a day. I had the feeling of passing out linger for about a week and went to the hospital to get test done. My liver was fine, blood pressure a little high on the top number but otherwise normal. That being stated the only thing I can think I've ever done wrong was when I was a kid a broken arm exposed me to opiates pretty early on. I never really had a problem with them, other then just enjoying the feeling to much.. but I found my moms stash of hydrocodone 10/500 one time and took about 6 for myself, I believe. Thee first dose I think was about 2, on the way on a trip to visit family about 3 hours a away. Then repeated dosing for the next day or so following. No adverse effects other then being extremely fucked up. I'm just wondering if that woulda caused my over sensitivity now to opiates or if you guys think I am just thinking to hard and causing placebo effect. I'm quitting them but I really cant tell you I won't ever take them again despite that fact. So i'd just kinda like input cause tolerance breaks are cool and give me a reason not to just keep upping my dose because of the sensitivity but I would like to just see what a 10mg felt like all at once.