Can you get a different doctor? I would first ask the doctor you have, tell him what you just wrote here and how it is dramatically helping you but you just want an easier way to get it. I probably would go with an attitude of "I'm smoking marijuana, and it is helping, can you give me the legality to grow/buy it on my own?" rather than "Marijuana has helped me medically, should I use it?"

I think going with the latter he'd be more inclined to say no, and continue with the usual meds, but that's just me assuming he's a typical doctor ignorant of the medical benefits of marijuana, hopefully he isn't, but I'd still go with the first. And if that doesn't work, try to get a new doctor, I know it's a pain in the ass, but really, if you aren't comfortable talking to your doctor about a certain controversial medication, he's not the right doctor for you anyway.