Fent withdrawal is brutal, and it's something you'll remember but IMO subs and coming off of them was wayyyy worse.Suboxone has so many different mechanisms besides covering the opiate withdrawal,the psychological "anti depressant" like action along with having basically the same withdrawals you have now plus those, I would avoid Suboxone and methadone for that matter as all your doing is actually prolonging the withdrawal symptoms. Not saying this is much better but have you tried kratom extracts? If it's legal where you are, Meng Da green vien or red Vien will help tremendously vs cold turkey. But they have to be legit extracts,and not some bs adulterated brand,I could suggest some. The thing about kratom extracts though,you build a tolerance very quickly which is a good thing using it to "step down". Myself was opiate addict for 16 yrs and to be honest the only way to stop once you've pushed it to the point is cold. The withdrawal as long as your hydrated and getting nutrients into your body will not kill you itself. It will feel like it. Worse is the months afterwards where your resetting basically your brains chemical receptors...but once that passes, and it does pass- you'll cringe thinking about injuring yourself ever by accident and NEEDING an opiate much less getting loaded. All above mentioned also will work miracles, especially for the insomnia. Support group. Stick with it.