You might be suffering from a depression. Depressions can be successfully treated with CBT, Cognitive Behavior Therapy. They can also be treated with medicines like Prozac. Negative thoughts can contribute to your depression. Try to think about what you want to happen and avoid tinking thoughts that makes you depressed.
Take responsibility for your actions. You don't have to be nasty to your boyfriend. Try to give him praise instead.
More about treatment of depression.