How to stop your brain from being negative when everything inside you wants to scream and cry?

Please get seen: It's a mistake to think you're in charge of your thoughts. You may have a physical problem that's making you think this. Your life situation may need to be adjusted in ways that your physician can help with. Short-term, medication has saved millions upon millions of people in your situation, restored them to a useful and happy life. It's not a sign of weakness to seek help like this. Go for it.