For example, you could have a conversation with your boss about extending the deadline or getting some extra support from coworkers.
Take a proactive approach. If you believe your fears are backed by evidence (for example, your boss has warned you that this deadline is important), look for a proactive solution. For example, you could have a conversation with your boss about extending the deadline or getting some extra support from coworkers. This is more productive than simply obsessing over the issue on your own.