When you are withdrawaling. Its the fear that makes it worse. Your body releases hormones that make the withdrawal many times worse. If you relax for a few minutes (jump in a hot shower) and think about how you are actually feeling, its not that bad. At least you can convince yourself that, and get past the intense fear that comes when withdrawal is starting, enough to make it 2-3 days off and it will be starting to subside before you know it.
Stopping opiates is hard. Only few can do it when they realize they now have a habit. And right now your habit isn't much, and its short. I wouldn't even bother tapering. Perhaps give it a try, but a cold turkey withdrawal will be the quickest way to feeling better. 99% of opiate tapers fail. Or just do 3 pills, 2 pills, 1 pill, .5 pills. 4 days. I have kicked huge opiate addictions, and small ones. They all suck. You just have to accept it, and get past it. Looking for a "pain free" way out is how the cycle continues, and usually the person ends up with another addiction on top of the one they already had (xanax being the #1 contender here). Being 23, you can kick its ass and be on your way.
There are plenty of comfort meds that will help. Anything over the counter. Of course weed (depends on the person and strain I would guess). I always found water, and ibuprofen helps the most to be honest during acute. Once you come out of acute, valerian root, meletonin, etc will help a lot.
But also, you are going to have to withdrawal while your boyfriend will be taking them? And he will be happily snoozing while you are quitting? And then there will still be pills laying around always? This is an issue. Just knowing its so close and easy to get will also make near impossible. I really have no solution for this aside leaving your boyfriend for a few months. You will need enough strength to be able to face opiates being right next to you. Perhaps another solution.
Stop sniffing them too in the meantime. Its ruining your sinuses. That will also drop your tolerance.
I will tell you an old tale in the methadone system. There was this kid on methadone. He was on a blind taper (they don't tell you how much they are giving you). One day he went into the clinic and the nurse told him...you haven't taken a drop of methadone in over a week. He immediately went into withdrawal and was demanding methadone. We have some kind of switch in our brain. As soon as it gets flipped on, we convince ourselves we are dying and cannot do it. You have to somehow figure out how to keep that switch off (you will not die, and you can do it). Good luck.