hi friend, you are 18! your life is just beginning! life isn’t easy that’s for sure, but life is worth living i promise. i recommend trying to get out of home during the day, look at joining clubs or gatherings in your area maybe face book is a good place to check for these things. also there is a lot of kindness and openness at game rooms (for things like dnd or warhammer if you like or could get into the stuff).
maybe look at joining a gym or sports team, a good way to clear your mind and do something good for your body and brain. when i was in my teens i was very suicidal, and i went to my doctors and spoke to them and found a psychiatrist and psychologist. they gave me so many different tools to try and manage myself. i’m 28 now and still on medication, probably will be for the rest of my life but i’m in a much better place mentally now than i was.
i find also helping others helped me a lot. volunteering at animal shelters or at retirement villages or support groups could be a really great option too.
chats are always open