Is negatively thinking about things like death and what life means a symptom of depression? my thinking has no answers so would a therapist be useless

NOT useless: A therapist would be USEFUL to you if you're frequently thinking of death. Yes, this could be symptoms of depression. Please talk to your parents, a therapist, your doctor, a school counselor, a pastor, etc. Help is available.

Not necessarily: but worth a consultation with a psychiatrist because indeed you may be suffering from major depression, which can be treated with psychotherapy or medication. Most worries have no answers - and that is exactly the kind of problem that psychotherapy is designed to help with.