Do I have depression, or is it just a phase?

So I'm a 14 year old girl, and since last September (I think) I've been feeling alone ALL the time (even when I'm with people), I've been super depressed, and actually started cutting. (I know it's bad, I'm trying to stop.) but I kinda got a little better around February/March, but now it's getting really bad again. My mom has severe depression, so I think I might have it? I've taken countless online tests and such on teen depression, and all of them said I most likely have depression. I've only told one person that I think I might have depression, but she didn't really care. I don't want to say anything to my parents cause it might just be a phase? Do you think it's a phase, or do you think I might have depression? Thanks in advance.