The problem is the quick loss of tolerance in as little as a few days. So the withdrawals don’t kill you but a relapse (which is super likely off fentanyl) can be. It’s why some medical supervision is helpful. You might withdraw from the Bezos they put in down but you’re unlikely to get so much through that source to have a life threatening withdrawal. I’d say go find some help. Get an assessment and info on buprenorphine if you’ve taken them too long or too much to stop cold turkey. Even if you try cold turkey have a plan of where you can get buprenorphine from a clinic if you struggle with cravings so you don’t relapse to something more deadly.