Suboxone is stronger than people give it credit for. Even if it is only a partial agonist. There have been times where I've gone from quality dope and then back on suboxone, expecting to be in withdrawals for days, only to need to take a long intense nap once back on the subs. Buprenorphine is roughly 40x more potent than morphine. Usually not recreational-wise, but the sedation sure can get heavy on suboxone. That MSContin may have not been holding you & since you went so long without subs, you basically got it all out of your body and those first doses back on subs were actually stronger than the MSContin. Sounds weird, I know, since MS is a full agonist, but it's still very possible. Especially combined with a benzo. 2mg of buprenorphine is roughly equivalent of 60mg of Morphine. If the morphine had still been in your system making your tired, then the suboxone would have given you precipitated withdrawals. Glad you're okay. I know this post is old, but I didn't see many people pointing out this perspective.