Can anyone help??Idk anymore?

I was depressed for a while and never really solved the problem and even though I act like everything is ok it's not and at first I just went around and didn't care about anything but recently I'm just sad when I'm by myself I get so sad and down about everything and noticed that I'm starting to have horrible anger problems and when it's really bad sometimes resort to cutting... I'm confused and at a loss...does anyone know what's wrong with me or what I can do to stop this... Please