5mg of methadone is a very low amount & its only been a wk. Either 5mg or 10mg is the lowest dose a doc will have you on before coming off completely. If you do find your in any pain or discomfort take some paracetamol or ibuprofen. My guess is that you'll be ok though. I had a friend that came off 10mg no problem & they had been taking it for a long time before. Good luck
You should or you're going to end up being real sick. Best detox is a slow detox.. Go down 1 or 2 mg a week and end at 1mg.