Many students underperform on exams due to experiencing high test anxiety. We report on a study comparing a novel intervention of seeking support from one's social network to the more common approaches of expressive writing and studying task-relevant materials for simulated open-ended test questions. We measured in-the-moment (state) anxiety before and after each intervention, and correctness of the solutions. We also surveyed students to learn about their perceptions of the interventions. Our results showed that social support decreased the anxiety of high test-anxious students by 21% with the reduction in anxiety correlating with the number of messages received. Social support also allowed high test-anxious students to score at the level of low test-anxious students. Expressive writing showed a similar effect, but increased the anxiety of low test-anxious students by 61%. Studying task materials had no effect on anxiety and high test-anxious students performed worse than low test-anxious students. Despite benefiting from social support, we found that students were uncomfortable soliciting support from their online social network. Realizing the benefits of this approach may therefore require different formulations of social support in practice.