Daily dose of DXM for depression

I am a 17 y.o male living in Australia currently in my last year of school. The way things are going for me psychologically I don't know if I'll be able to do well and fear I will go nowhere. I have struggled with addiction since age 15 with opiates and amphetamines because it was the only thing that managed to fill the void and motivated me to do anything of any value for anyone, including myself. I have recently moved away from the town in which I have lived my whole life and for the most part renounced using illicit psychoactive chemicals to help me get through the day because of how destructive it was for my life. But recently the feelings of depression and emptiness have been returning. I got a hold of some morphine and took 75mg orally and I realised why I had been using. I can feel okay at best. But it seems without medication I am never truly happy. I was wondering about starting something routinely. I'm not a fan of SSRIs because I've seen what it's done to a lot of people and its anything but effective. SNRIs seem ridiculous, why anyone would want to inhibit reuptake of norepinephrine is beyond me. It seems as if it is only the negative effects of dopamine. I think a dopamine reuptake inhibitor would alleviate a lot of these symptoms for me but in Australia laws are tight. I can't see myself getting a prescription for methylphenidate for depression. I was thinking perhaps a controlled oral daily dose of 60mg of DXM HBr would work wonders. The times I've taken it have helped greatly. What do you think? Would this have negative effects on my cognitive abilities or help?????