The drugs are the cure until they become the problem.
It sounds like the drugs are what need evaluating, not prescribing.
Any time I needed weed were the times when I actually didn't. You don't need weed. Get yourself into a funk and you might think you do but just because you are in that place doesn't mean you got there doing the right things and based on the best decisions. I personally started smoking weed because of peer pressure which then turned into me using it as a crutch for practically everything, mainly escaping my responsibilities as I got older and had to do stuff that was important and would help me. Now I look back, just as many do when they get sober, and wonder why the f*ck I actually believed what I believed. Some of the things I did were crazy, and all to get a smoke because "I needed it". You will do crazy things when you're in those places and to make it worse, do you realize you've got a problem at that moment in your life? Of course not.
I don't think the speed is helping either. If it was me I would use the speed as an upper so I felt good about how shitty my life actually was back then, and the weed to smooth out the come downs. So it's not that you actually NEED the weed. You might NEED the weed because you crave something to make the speed benders more tolerable. And so it's the speed benders that are the problem, and the weed is simply a coping mechanism, a crutch, for how shit you feel after coming down from the speed. You wouldn't feel like shit if you weren't abusing speed. You probably also wouldn't feel like shit if you weren't putting so much weight on weed holding you up when the decisions you have made back fire. Weed can't solve your own desire to do these things to yourself. Weed is just dried plant matter. It feels nothing for you. It doesn't care. It doesn't know your story. But weed can help, literally, to create a smoke screen, so you believe temporarily the problems have gone away. It's whatever you choose to do with weed. If you want to run from problems in your life it will become the drug of choice to escape. As will any drug though I suppose.
Again, it's not the drugs you should be looking at. It's your decision to take them. There is a story BEFORE the drugs. There are reasons as to why you take them in the first place. That needs to be addressed. It's all too easy to run with the same script looking for the fix at the end of it all but if the fix actually did anything for you, would you need to keep taking the drugs? If you could get some weed now would it solve your issues? Probably not. If you're like most of us you'd soon repeat the cycle that got you wanting/needing the weed in the first place (which would be because you took other drugs and made other choices and now you need weed as a crutch) and here we are, right back at the start with the same problem and the same solution that doesn't work. So if you take the drugs away and you are exposed to life without them, what presents itself that needs to be addressed? The reasons why you took the drugs in the first place, and now you're making progress. This is where the real core of the issues are