You shouldn't be too quick to blame yourself for things.
Howie took a big test and received it back with a poor grade.
Howie wants to react to the grade.
Howie takes a day off and then goes over what he did wrong on the test.
Howie immediately thinks to himself that he's just not intelligent enough to do well on tests.
Howie will be able to assess where he went wrong and improve.
Howie will set limits to himself and no be able to achieve much.