If the depression is really affecting ur life then go see a doctor and get on meds for a little bit. I'd suggest trying therapy thou, either alone or long with the medication. But I personally not really into just taking a medication w/o trying to deal with the issues.
Ur depression is caused by PAWS thou and it will get better most likely on it own. Try getting occupied, clean ur house, read some books, exercise, go out. IF u don't feel like doing these things force urself to do them as I guarantee that eventually if not the same day they will make u feel better.
I know u feel depressed but think about how much better ur life will be not being a slave to drugs anymore. U r a free man. Since ur depression is most likely just caused by PAWS and it will pass then adding another drug is not the best idea. Just wait it out and it will get better once ur brain returns to what it was before u were on drugs.
Antidepressants have a w/d and problems of their own. They are not a magical fix for depression. It might be difficult to get off them and they might make u feel worse. U have already come all this way then hang on a little longer and don't jump quickly into the hands of another drug. Antidepressants are another drug, just like methadone. Try everything else to fix ur depression and then in a few months or so if it's still bad then yeah try an antidepressant but as a lost resort type of thing.
I am also off opiates and even thou I am depression prone, I am not depressed anymore. I didn't want to take ADs as I had bad experiences with them before. My depression lasted a good few months and I did actually try an AD which didn't help. After switching ADs for a few months and still not getting good results I just said fuck it and tried to treat my depression naturally which led to me not being depressed anymore. I try to just be happy with what I have and how things are. I try not to get stressed over little things. The only thing that ADs did for me is make me not be able to get an orgasm, but I guess they do work for some people so it's a personal choice type of thing. But in ur case I'd try to wait it out or try other ways of treating depression.