I am not quite sure what is going on with me. There have been many times within the past couple weeks that I've been feeling sad and depressed for no real reason. I find myself close to tears or actually crying and I don't know why. There is nothing going on that I feel I should be depressed about.
I met a guy a couple months back. We've been going out and I have a lot of fun with him and feel happy when we're together. Also a couple months ago I moved about two hours away from home and started attending a new school. I decided to change my career path and I know for sure this is what I want to do. I'm getting straight A's for the first time in my life. I also just got a new job recently that I really like so far. It's night shift, so I have to adjust to it. But I'm not sure how that would have me feeling this way. Everyone has been good with my family and my friends.
It's weird. I don't know if it's because of all the changes or what. I can't really find anything that would be making me sad. Is it just some kind of depression? And how can I feel better?

Depression is one of the most under diagnosed conditions that adults have; all of us have been 'blue', but there is a big difference between short-term feeling down, such as the loss of a relationship, and overwhelming depression that affects every aspect of your life.

When weeks go by, and the feelings and symptoms increase, you may be clinically depressed. It is treatable, and highly effective medications are available, and a talk to your GP will help to determine what the best course of action is.

If this does become something that is lasting, and you experience any of the following, I urge you not to suffer with depression, and get help. It may very well be caused by all the changes you've recently been through, even though they are positive changes, they may be adversely affecting you.

Take a look at this:

Are you clinically depressed?
If you identify with several of the following signs and symptoms, and they just won’t go away, you may be suffering from clinical depression.

You can’t sleep enough or you sleep too much
You can’t concentrate or find that previously easy tasks are now difficult
You feel worthless and hopeless
You can’t control your negative thoughts, no matter how much you try
You have lost your appetite or you can’t stop eating
You are constantly irritated or become enraged even at small things – and this is new for you
You have thoughts that life is not worth living, or have a plan for how you would end it (Seek help immediately if this is the case)

This will give you some idea, or clues as to the difference between a transient period of feeling blue, and being clinically depressed. It very well might be just a short term thing with you, and you'll be feeling back to normal in no time. But, please don't hesitate to get help if your situation gets worse.

Here is more information:

Depression: Signs, Symptoms, Types and Ways to Get Help (http://www.helpguide.org/mental/depression_signs_types_diagnosis_treatment.htm)

Depression without cause is worrying seek help from a professional psychologist