Exercise definitely helps. If you can motivate yourself to do it by thinking about how much better you'll feel afterwards, than do it. But don't expect exercise to magically cure your troubles completely.

You definitely sound like you're experiencing depression. In my case, the two sides of the coin are anxiety and depression. Anxiety is the dread and panic fear of what's going to happen to you, and depression is the feeling of irrevocable loss, of mourning over an internal deficiency or a lost future that can never be realized. Anxiety is terror, but depression is contemplative sadness over the void of your life. Loss of energy is a big sign. Another sign for males, if you've experienced it, is getting more easily angry than you would otherwise. Most all of what you said is extremely similar to what I've experienced as the depression face of the coin.

There's things you can do which don't require a shrink, but do require you to stick to them regularly and to get over feeling silly for doing them (it's a common reaction, not that I'd expect you in particular to react this way). One thing to write is a pride and gratitude journal. Seriously think about something you did that day which you're proud of and something that you're thankful for in your life that impacted you that day. It's not a huge step, but if you take doing this seriously and do it everyday, after a while it could make a difference.

Beyond this, you might want to learn about "cognitive distortions," which are ways in which our minds distort reality to make things seem worse than they really are. That can help you start rationally identifying in what ways your perceptions of your life are distorted, and writing down evidence against and for these distorted perceptions can also help.


(God... I've been doing this fuzzy affirmation therapy bullshit for too long.)