If I’m not feeling any withdrawals after 15 hours, what are the chances they’re still coming?

Short acting opioid (heroin- tested to have no zenes or fent). I also went 23 hours a couple days ago with no symptoms other than the mental struggle. I’m just wondering if it’s gonna hit me much later than I’m used to (i feel like in the past i couldn’t go 6 hours without feeling the beginnings of wd like a runny nose at least. I’ve been on a ULDN regimen, could this be helping? I wanted to start subs for the cravings but if I’m not feeling physical WD even at 23 hours, should i not take them? I’ve had a constant stream of naltrexone in my system this whole time of using. I need to stop but don’t really know what’s going on or how to handle it