there are many sorts of medication, they work by positively increasing the amount of serotonin in your brain, lack of serotonin is a cause and/or a consequence of clinical depression.
this would be what they call depression caused by a chemical imbalance.You still need therapy or at least self-therapy to work past the damage depression has done on your thinking and behavioral patterns anyhow but maybe you'll just recover with the meds.

you of course should get diagnosed by a professional but depression for so many years is definitely not the sign of a mild depression,on top of that losing all motivation and escaping into an addiction (which is normal,I escaped into gaming back then))

You just gotta tell everyone man, you can read the stories on this sub.this is no illness to mess with, it certainly wont get better on its own,it will only keep wearing you down, most people dont want to go therapist to take meds,I know its scary and so uncertain, but as most people in the end you just crack down,suffocated by depression and the damage to your own life and you're forced to go out there and try.

id suggest not waiting until that moment, you will have to face your depression eventually, depression can't be ignored.

I know it takes a lot but I believe you can do it, one word of encouragement, once you do it, reach out to a doctor or anyone, you'll see its not as hard as you thought,everytime I told a friend or my parents or a doctor it ended up not being as hard.
a good doctor deals with hundreds of patients with mental illnesses, they will understand and they wont judge,and its not as life-changing either,this is a slow fight,healing from depression is very slow, be it through meds and/or therapy, thats why its good to start early.
I haven't been cured of mine, so I can only guarantee what I know, so far I feel better and thats a lot to me, I definitely guarantee you can feel better too!