Hey,
You definitely sound like you are going through a phase of depression and I don't blame you at all especially since you lost your friend in a car crash. It is never easy to deal with a loss of a friend or a family member and it often leaves us feeling really lost and questionable about life. I do believe it is just a phase and you will get over it but i also think that you should seek a psychologist especially since you are having suicidal thoughts. It is always best to seek professional help and to just lay it all out the table. They will understand your thoughts and feelings and will be able to advise you. I do wish you all the best and I wish that get through this and remember this saying ' tough times don't last, tough people do' :)
I think counseling would help. Doesn't sound like clinical depression to me, it just sounds like you are grieving the loss of your friend. I am so sorry about that by the way, my best friend died in a car accident as well and it was really hard to deal with. :( Therapy will help you go through the steps of loss and grieving in the healthiest way possible so you can get back to your daily life... It gets easier with time.. best of luck to you hun.