How are you doing it? Like after you use, how long do you wait before taking sub? Also you might not be taking enough. Most doctor's make you take 8mg. Usually you need a lot when you induct. And I'm not sure why you puked. I had a friend who took sub but she wasn't hooked on opiates and she took an 8mg strip and ended up basically high af and puked because of how strong it was. Maybe that's sort of why you puked? But idk. It could just be from wd. Do you normally puke when you're in moderate to heavy wd?
You're body/brain is definitely fighting the sub. Your brain just needs to get used to it. I'm sure if you just keep trying everyday, eventually it will stick. Personally whether you use or not, I think you should be taking subs everyday so you could get your brain to recognize it better and get used to it and so you can build of bupe into your system. But that's just me. Once you build up enough over a few days in a row, then you can wait 20 hours and take only sub and see what happens. Idk but no matter what your gonna have to deal with some uncomfortability.