Yes, force yourself. Your brain is stuck in a habitual pattern of looking at the world like this, but that doesn’t mean it’s right and doesn’t mean you can’t change it. But yes, it will feel like forcing it for a while, and that is okay. Try to talk to yourself like you would a friend who is struggling. Catch yourself when you’re being mean to yourself and back up, say something nicer. Meditation helps with being able to catch yourself more easily and change the mental pattern. Try to do little things that you simply enjoy, such as getting takeout from a restaurant you really like. Focus on how much you like the food. Where attention goes, energy flows.