I'm depressed but i'm too scared to tell anyone in case they think i'm lying especially my family, what should i do?

Secret depression: Depression is serious, and you express concern about your family knowing how you feel. If you're in college, there's a student health service with nurses, doctors, and counselors to talk to. In high school, there are school nurses & teachers -- but they may need to encourage help from your parents. You can speak with your primary care doctor, and s/he can help you -- along with family if needed.