Hi and welcome,
That's a shame your doctor was not more supportive when you needed.
There's plenty of good advice and support here on SR. Aside from your physical detox/withdrawal from the drug which you seem to have covered you may wish to consider NA meetings. Even once don't have the drug in your system any more you may find coping with life difficult, particularly with the underlying issues with pain and your health. A 12 program can really help......it's also a great way of connecting with people face to face who have had similar addictions to drugs.
Take care.