Typically, taking downer drugs, and opiates are downer drugs, make people feel better while they're on them and more depressed when they're not. It's not like taking an antidepressant, which once your brain gets used to it and it works, it keeps working all the time. You don't say if this was prescribed or you're using it on your own. It's value was to help addicts avoid the horrible withdrawals of stopping to bridge them over to not using at all, but if you keep using it it's no different really than using opiates. You haven't really quit. If the opiates didn't solve your depression problems, it's unlikely this will, but people are different -- who knows? A question you want to ask is if it has any adverse interactions with the cocktail of antidepressants you're taking. I think suboxone shouldn't be combined with benzos, but I don't know about antidepressants and the two you're taking work differently. I think the mood changes are the same as anyone who uses drugs recreationally to the point of becoming dependent on them -- you're up if you take enough and you're down when it wears off. You don't say if you were on the hydrocodone for pain relief or fun, so we don't know the nature of that. The problem with taking drugs that create euphoria is it usually takes more and more to get the same feeling. That's usually not true of antidepressants unless they poop out on you, which can happen after a long time on them. No drug is going to cure your depression, though -- the best they can do is make you feel better. If there is a cure it's through therapy or other lifestyle changes or just time sometimes but since medicine doesn't know the biological cause of depression there's no pill to treat that cause, they just treat symptoms. Same with opiates.
This is just my opinion, I don't judge. I took Suboxone to get off hydrocodone. I believe both of these meds dont help depression. After getting off sub, I went back to pain meds, very ignorant of me because I felt better without these drugs. I have insomnia really bad and I take Xanax, not good for depression either. I take Percocet, for pain from shingles, 2 years I've had it. I want to wish you the best. You can beat this, I'm gonna beat it.