Depression is a chemical state that your brain becomes accustomed to. You don't become depressed after being sad one time, or getting one piece of bad news, and you can't snap out of depression with one instance of good news. It either takes medication to resolve the chemical imbalance or active and concentrated effort to retrain your mind and thoughts to focus on positives rather than negatives. Or more often and more effectively, a combination of both. People can come out of a true depression without medication, Im not trying to say it's necessary, but it makes the work of rewriting your neural pathways a lot easier. Other alternatives are therapy, CBT, meditation, a change in habits such as better diet, more exercise, better sleep. Your depression may have been caused by politics getting you down initially, but it's built up over a long time, and those pathways in your brain have become ingrained until they are the path of least resistance. One case of good news is not enough to just magically fix that. The good news can be a big start if you let it, but it still requires some method or combination of methods to retrain your brain to focus on positive things, to undo all the time that you've spent focusing on negative ones.