Having a Routine
If you are feeling anxious, you should sit down and ask yourself why. If the answer is "I don't know what I should be doing right now," maybe you should think about having a daily routine. Then the answer to the question is simple: you should do whatever comes next in the routine. Do whatever comes next, and don't let your anxious mind fool you into coming up with new things to worry about to distract you from your routine. You might start to think "No, the real problem is I don't know what I should be doing with my life!" This is probably not true. You probably do know. Go back to the routine and laugh at yourself. But if you really don't know what you should do with your life, you should sit down right now and figure that out.