To have depression do you have to be sad?

Sadness is THE hallmark of depression. Feeling unmotivated, dull, and "emotionless" as you put it are also secondary symptoms of depression, but an overwhelming feeling of sadness and hopelessness is the primary, hallmark symptom of depression.

Here are the DSM criteria for diagnosing a major depressive episode:

http://www.mental-health-today.com/dep/dsm.htm

The requirement is that you MUST have either depressed mood, or loss of interest/pleasure with life in general. When you say you feel "dull", does that mean you don't get pleasure out of the things in life anymore, or that you've simply lost interest in life? If so, then you may be depressed. If you just feel bored with life, that's not really depression, that's just boredom.

If a lot of those symptoms (at least 5) sound like you, then you may be suffering from a depressive episode. You could opt for medication, or you could try seeing a therapist first. Not all people need medication, many can get relief from therapy alone and never need to take a pill. Other people get very little relief from therapy, and medication is necessary, particularly in severe cases. Some people do best on both. Your doctor can help you decide what the best option is for you.

Good luck!

Very much so. In fact, those are the classic symptoms of depression. If there is nothing in your life recently that triggered it (called situational depression-may not need medication), it may be that you have a biochemical imbalance. Talk to your parents, friends, and doctors about what they think and maybe you can go on medication. I did and it has made a world of difference to me. Don't give up if it doesn't work immediately, it may take a few weeks for it to feel better.

Good luck and keep trying!