depression from happening, but you have to deal with it when it happens and stop it form taking over you.

You can feel all of a sudden that you are depressed because of the unknown. It could be sort of sad feeling, being uncomfortable, make you unable to even breath.

Try to have some good company, they would cheer you up when you feel down. They won't let you be sad and do nothing, they will try their best to get you out of it if they really care.

Stop looking for answers to the hundreds of questions in your mind, stop wondering what tomorrow would bring [what if tomorrow never comes?], try to be optimistic, stop thinking that bad things would only happen, don't be afraid to be alone it's sometimes good to be by yourself.

Always have in mind that God is there, pray asking for help, for peace of mind, for success and happiness.

Do not dwell in the past, do not dream of the future, concentrate the mind on the present moment. (Gautama Buddha)