I would describe fent feel like a dream. Other opioids or opiates--synthetic or not--seem to have a nice taper off as the high recedes. With fent it seems to be a mind-blowing feeling for people like us, but then it disappears quickly and "that's all that was" before the redose. Its not a pretty life and it wouldn't be hard to do fent for life if given the finances/opportunity to waste it away until death lol.
The mental aspect of the withdrawal is
brutal. Had zero physical symptoms other than some mild obvious ones like appetite gone/issues sleeping/very low energy. Personally I don't think fent is worth it because its just a dream-like state that doesn't really much allow you to experience life in any format other than staring at a wall like a slug and being content with your situation. I've never experienced the struggling to breathe properly that you are dealing with. However, I'm not sure if thats a dosage thing or your body's particular negative reaction to the drug. It sounds very serious and concerning, and that can't be a good omen for continuing to use on the regular.
I recommend looking into suboxone/methadone if you really cannot quit and would absolutely reach the point where you can't take it anymore. I had the misfortune of cold-turkeying a pressed fent pill crusade and just want to say, I would never do it without suboxone again if I so much as touch fent within my future a bit too many times. Do you think you may be willing to try getting on suboxone if you cannot stop? Its a powerful feeling.. many junkies despise fent because "it has zero euphoria and only nodding out" as the high. For others like us it seems to be one of the best feelings possible, and something like it will obviously defeat so many people who enjoy the substance no matter the will-power involved. The temptation is too grand to resist for some mortals

. I don't really think about fent much now but I do remember the days lol. I wouldn't say life is "boring" without it but it definitely is a hard adjustment and the happiness off opiates does not come when you want it to per say. Recalling staring at the wall doing nothing and being blown away by the sensation despite the nods and etcetera. No other substance that I've personally used allowed me to stare at paint drying and still be completely satisfied with my life while doing nothing at all. That can't be too entertaining for long you know? At least the perpetual boredom of sobriety allows your life to be slightly more interesting than being a blob, though. After 2 months of experiencing it all, my supply permanently ran out and I never really wanted to seek it out after how pleasurable it felt... this might've been around early 2020.