Am I correct in saying that you have a pretty good understanding as to the source of much of your anxiety. Comparing yourself with others and being obsessed with grades? And that so far work with your therapist has not help you with finding ways to stop that unhelpful behavior…I assume you recognize that behavior as being unhelpful but for unknown reasons can’t stop yourself?

When we know a behavior isn’t working for us but continue anyway its likely that there is an unconscious payoff. Something you want more then wanting to end the anxiety the behavior creates. If that is true the next step would be to work with your therapist and identify what the payoff is and then deal with the source of the issue behind your need to compare yourself with others and obsess over grades.

In the mean time you can try the practice mindfulness – when you notice you are comparing yourself with others. Stop, create some space to breathe, notice the anxiety without judging it. Remind yourself that comparing yourself against others is not helpful and direct your thoughts else where.