Serious mental health post.

I have been facing mental health issues like depression from last 30 months. I have been taking medicines for it since 11 months. I don't feel better. I am still confused and depressed. I want to die. I just don't want to live with this pain but i cannot kill myself because my parents will feel sad and I am coward and unable to kill myself. Nothing is working out. I took a gap year after 12th because I was depressed and doctor told me to rest. Now, I joined a tier 4 college in bcs and I hate it. Problem is now i don't even study at home properly. My dream was to study space science and cosmology and make a space tech startup. I was very hopeful that I will do it. But nothing works now. What do I do ? Please reply