Gb welcome to the forum.
You have gotten alot of good advice so far as usual here.
I dont know what your Doc is saying or why but you can find alot of info on a methadone thread here but I am going to cut some of it for you now.
Methadone hits on a completely different receptor in the brain then does any other opiate and in saying that I am saying oxy hits on an altogether different on so telling someone they arent going to "feel" w/ds from any opiates is well an uneducated guess in my book,not saying your Doc isnt good just saying he might not be all that versed in methadone therapy and alot of them arent.
Like they said you need to titrate down slowly treat the withdrawl symptoms the best you can and before you know it should be good as new. If your not dont hesitate to look for something else going on,those symptoms can be ones that go to alot of things. Too many times those of us on higher doses of pain meds get miss diagnosed because we may be NOT feeling the pain from say a heart problem,our pain meds block that pain that is normal to warn us something is going on with our bodies. I cant say this enough to anyone,if your showing some kind of signs of somehting going on and it is different then what you normally feel or if it last longer then you think it should get to the Doc and make them listen.
I am not trying to scare here but offer advise.
My best friend ended up with a ruptured appendix,simple little thing but because he didnt "feel" the pain due to high doses of methadone via the clinic it turned deadly and he spent months after surgery battling septicemia from the rupture and almost lost his life.