To be honest getting a diagnosis of clinical depression is very difficult if you're under 18 in my experience. I was referred to cahms when I was 12 due to symptoms of depression, I have only just gotten diagnosed recently, I am 17 now. The thing is doctors really dislike diagnosing depression as depression, instead they may diagnose you with "low mood" if you are diagnosed with this it is the same as receiving a diagnosis of depression at least internally. By this I mean doctors will give you treatment and treat you the same as anyone diagnosed with depressive disorder, it's just that external bodies like your school, job ect.. that wont treat it as a valid diagnosis. I had to practically beg my psychiatrist to diagnose me properly. To get a diagnosis you need to go through your gp to cahms if you're under 18. If not you need a referral from a school councillor or someone else of that nature. You can try to do a self referral but it's very hard to get seen. It will take months of back and forth with a psychiatrist once they finally allow you to see one to get a diagnosis. I know I've painted a very bleak picture here but at least in my experience diagnosis is a very long and painful process that may take years to complete. Self diagnosis is okay until you can get one, please don't wait until a diagnosis to understand and support yourself. I wish you luck on your journey :3