I think I have depression but I can't tell my family.... Please give me advice?

I started loosing motivation for exercise and just want to eat sugary things or nothing at all, I can't sleep at all, and I find my self questioning my worth or Whether I should be living. I took some online test and they said I was depressed. I want to go to a doctor to talk about it, but I CANT!
I live with my dad and doesn't understand or care for mental illnesses and I can't tell my mum... What can I do? I want to get help I hate feeling this way. Please tell me what I can do.