I'm hearing from a lot of clients at the moment that they are a bit stuck in the anxiety/catastrophising loop and that makes me a bit sad. We tend to believe that we can only think one way and that our brains control us, when in fact, the opposite is true. Our thoughts are only thoughts, generated by ourselves and no-one else, so in terms of what you think, it's all down to you.
You can effectively choose what to think in any given situation. Choosing to think 'this is all terrible', for example, becomes a habit and builds a strong neural pathway that your brain defaults to. Have you heard of neuroplasticity? It effectively means that your brain can change.
How does it change? It changes because you practise new ways of thinking. The more you think the new way, the stronger the neural pathway to that way of thinking becomes. And what happens then? Your brain learns to default to the new way.
So if you're fed up with the catastrophising, call it out for what it is - it's just a thought. Decide what thought you want to replace it with (This will end soon and we will find a way through, for example) and practise thinking the new thought. It will reduce your anxiety levels and help you to think more clearly about how you will actually find a way through.