Had any suicidal thoughts ? Because even if you haven't had those yet, I'd still prefer you seeking professional help. There are actual therapists everywhere on this site, and I would really like you to contact them instead of us :)
I know it's scary, and this might not be the answer you were hoping for, but depression is a very long and hard battle just like cancer. you have a bigger chance of finding a solution with a professional :3
I think you should try to seek help in a friend or family member but if you cant then maybe a doctor or teacher or someone. Depression can be on many different levels and i think you would be good to seek help and advice now you have realised its taking over your life rather than later on when it has become worse. I hope you find someone to confide in soon.
Okay my response might sound a little off and different from the rest you got, but no disrespect to any of the people who have said this or answered....but that's not what you should do just yet.
I have been dealing with depression since I was about 8 years old. I've done it all, counseling at school, therapy you name it. First thing you should do is research depression and find someone who has been through it. No one understands depression better than someone who is depressed. I still deal with it now. The sad truth is that many people who claim to be there to help will often pass judgment on you. Most of them will talk to you and you think they understand you when their notes will say other wise. Tell someone close to you if you can trust them. Start on the inside before the out. Work your way up to professional help. I am able to talk with you and keep tabs if you need me to. Just message me.