For a couple of years now I’ve been dealing with depression. Up until now I’ve dismissed it because I figured I know people who have it way worse than me so why would I be depressed? But the days have been getting harder and harder to the point where I often find myself thinking about ending my self. Usually after isolating myself for a while I feel slightly better and dismiss the episode as me being a dramatic 15 year old . But now all I think about is doing it. I often do things to give myself momentary joy but my family has started to question it and I have to lie to avoid confrontation. It’s even harder when we see news stories about teens killing themselves and their only reaction is “you teenagers have no responsibilities these days you have no reason to kill yourselves”. Getting up everyday feels like swimming through thick grey water and I’m slowly suffocating. I don’t know how I can look my mom in the face and say that don’t want to be alive anymore

I can only suggest you accept your parents not understanding your problems and issues very well, it's not really their fault completely, but you do need an adult in your life that does. Maybe an aunt, or grandparent, or a teacher or family doctor. Are any of these a possibility to reach out too? Where are you in the world and of what culture are you?

Parents can not always, maybe almost never fully understand how a teen feels. to be honest a teen often does not really understand their own feelings. They have highs and lows all the time, and they compare what they feel to what other teens say they feel, and what others twitter, facebook or what ever says they feel.
So talk to a counselor at school, But just be honest with parents, they may not understand but you at least can be honest