Hi there! I think it is a vicious cycle. If we continually do things that make us unhappy with ourselves, then we being the downward spiral. If that continues long enough, then we do experience brain chemical changes and true depression takes over. Keep doing what you know to be good and right, but also get some professional help to pull you up out of the spiral.
Depression tells us lies. Don't listen to the negative, though it will be in your thinking.
You did a good job using this site and this forum
PS College is a tough cookie to eat... but well worth it. TC!