i have also been on
methadone for a long time, and other opiates.
120 is a fairly high dose, only you know how you feel, and dont let "the doctors" tell you when to drop, its your decision.
when you are feeling up to it, ask to drop by 10mg, see how you go.
it is a slow one, and i have done it also, got right down to 1mg, and still suffered, mind you i was also doing other drugs as well. i suffered for weeks with wd. it was awful. i got back into it again, few years later. so this time round, i have done it differently,
personally for me, i got down to 20-30mg of methadone, and jumped over to subs, which are a lot easier to taper down on.
i can say that honestly, because in my case, i could not count off the methadone again. its is really hard.
i started on 14 mg of sub, and am now on 1.25mg, just starting to have some cramping issues, so i know my body is feeling it now.
you know your own self, when you are feeling confident, just take baby steps and go for a 5 or 10mg drop. see how you feel.
i also know all the bs involved in clinics, i am off the methadone, but on subs, and still it is through a clinic, although i have found on subs i have never once taken more than i should have, as opposed to meth, which i always would have more if it was available.
just some ideas for you. good luck
oh and just stay on your new dose till you feel ok to move on. theres no hurry.